An element is a substance made from only one type of atom. For example, Oxygen ( ) is an element made up of ONLY oxygen atoms. To understand this better, let us see the how atoms behave.
Every element is made up of atoms.
Atoms are the smallest piece that can exist in an element. You will need to put
millions of atoms together to get an element of about half millimeter in size.
An atom is made up of ‘Electrons, Protons and Neutrons’.
The diagram on your left is an illustration of an atom. The center part is the nucleus.
Atoms in some elements do not join up with other atoms of the same element. An example is Helium. Helium atoms exist alone and can look like this:
The diagram on your left is an illustration of an atom. The center part is the nucleus.
Atoms in some elements do not join up with other atoms of the same element. An example is Helium. Helium atoms exist alone and can look like this:
Some
atoms can also join up with other atoms of
the same element. When two or more atoms join up, they form a molecule. Oxygen, (
) is a
molecule because it has two atoms joined together. An oxygen molecule looks
like those in the diagram above.
Elements are pure in nature. They may vary in size as long as the atoms joining to make its molecules are the same. As soon as a different atom joins (bonds), it ceases to be an element — it is now a compound.
Sometimes, atoms can join up
with other atoms of other elements in chemical bonds. When that happens, a
compound is formed. This means that a molecule can be made up of two atoms of
the same element, OR can be made up more atoms of different elements.
Known elements exist in the form of metals, not metals (non-metals), and semi metal.
1. Metal Elements
Metals are elements that have shiny properties and are generally good conductor of electricity and heat conductor. Metal elements are generally solid at normal temperatures and pressures, except for mercury in the form of liquid. In general, metal elements can be forged so that can be formed into other objects.
2. Non Metal Elements
The non-metallic element is an element which has no metallic properties. In general, non-metallic elements are gaseous and solid at normal temperature and pressure. Examples of non-metallic elements in the form of gases are oxygen, nitrogen, and helium. Examples of non-metallic elements in solid form are sulfur, carbon, phosphorus, and iodine. Non-metallic solids are usually hard and brittle. Non-metallic element in the form of liquid is bromine.
3. Semi Metal Elements
In addition to metal and nonmetal elements there is also a semilogam element or known as a metaloid. Metaloid is an element that has metallic and nonmetal properties. Semilogam element is usually semiconductor. What is a semiconductor? Semiconductor materials can not conduct electricity well at low temperatures, but their electrical conductivity becomes better when the temperature is higher.
All known substances can be classified as solids,
liquids, gases, or plasma. In addition, a fifth state of matter, the
Bose-Einstein condensate has been discovered recently. However, it is not
stable at normal earth conditions. Likewise, although plasma is the most
abundant state of matter in the Universe, it is not common on the Earth under
normal conditions, except for lightning. Most matter that students are familiar
with will therefore be in a solid, liquid, or gaseous state.
An element is a pure substance that cannot be decomposed into simpler substances by normal chemical means. There are 109 different elements. Ninety of these are naturally occurring; the rest have been created in laboratories. Elements 110 and 118 are still being researched on. There will be more elements as technology can identify them. A symbol is used to represent the full name of an element. For example, H represents hydrogen; O represents oxygen, and Al represents aluminum. Sometimes the Latin name for an element is used as the basis for its symbol, for instance K represents potassium (kalium in Latin).
Three subatomic particles compose elements: protons, neutrons, and electrons. Protons, which have an electrical charge of +1, and neutrons, which have a neutral charge, make up the nucleus of an element. This nucleus is surrounded by a "cloud" of electrons, each of which as a charge of -1. The electrons spin around the nucleus in what are called orbits or shells. Each of the orbits can contain a set number of electrons. For instance, the first orbital from the nucleus has 2 electrons, the second has 8, the third has 8, the 4th has 16 and the fifth has 32, and so on. Each shell may not be full, depending on the number of electrons in the element, and the inner shells fill before the outer shells fill. Sodium, for example, has 11 electrons, which are located in the first, second, and third shells (2+8+1.)
An element has a uniform composition. Different elements may join together; these combinations are called compounds. A compound can be separated into its component elements by chemical means. For example, common table salt is a compound made of two elements: sodium and chlorine. Table salt can be broken down into sodium and chlorine by mixing it with water. However, sodium and chlorine cannot be easily broken down into any simpler forms.
An element is a pure substance that cannot be decomposed into simpler substances by normal chemical means. There are 109 different elements. Ninety of these are naturally occurring; the rest have been created in laboratories. Elements 110 and 118 are still being researched on. There will be more elements as technology can identify them. A symbol is used to represent the full name of an element. For example, H represents hydrogen; O represents oxygen, and Al represents aluminum. Sometimes the Latin name for an element is used as the basis for its symbol, for instance K represents potassium (kalium in Latin).
Three subatomic particles compose elements: protons, neutrons, and electrons. Protons, which have an electrical charge of +1, and neutrons, which have a neutral charge, make up the nucleus of an element. This nucleus is surrounded by a "cloud" of electrons, each of which as a charge of -1. The electrons spin around the nucleus in what are called orbits or shells. Each of the orbits can contain a set number of electrons. For instance, the first orbital from the nucleus has 2 electrons, the second has 8, the third has 8, the 4th has 16 and the fifth has 32, and so on. Each shell may not be full, depending on the number of electrons in the element, and the inner shells fill before the outer shells fill. Sodium, for example, has 11 electrons, which are located in the first, second, and third shells (2+8+1.)
An element has a uniform composition. Different elements may join together; these combinations are called compounds. A compound can be separated into its component elements by chemical means. For example, common table salt is a compound made of two elements: sodium and chlorine. Table salt can be broken down into sodium and chlorine by mixing it with water. However, sodium and chlorine cannot be easily broken down into any simpler forms.
PROCEDURE:
- Discuss the properties of elements with the students. Review the structure of the periodic table. Ask students questions about the different elements and see if they can locate them on the periodic table.
2. Review the difference between an element and a
compound. The students should realize that an element cannot be broken down,
whereas a compound can be subdivided into elements. You may wish to explain
that in many instances, forming or breaking down a compound requires energy.
For example, if you place a mixture of iron and sulfur in a bowl, they will not
react. No compound will form. However, if iron and sulfur are mixed and then
heated, they will combine and form a compound.
3. Write the following examples of compounds and their
constituent elements on the board. At this point, do not be concerned with
explaining the "endings" to the chemical words, such as chlorine
versus chloride. These endings reflect the molecular structure of the compound.
ELEMENTS
|
COMPOUNDS
|
Na-sodium
|
NaCl (sodium chloride)
|
Cl-chlorine
|
AgCl (silver chloride)
|
K-potassium
|
KCl (potassium chloride)
|
Ag-silver
|
KClO (potassium perchlorate)
|
O-oxygen
|
H2O
(water)
|
4. Use the Periodic Table placemats to explore elements
with the students. When they examine the chart, the students may ask the meaning
of the numbers surrounding the element symbols. The number in the upper left
corner is the atomic number, i.e., the number of protons inside the
nucleus of the element. The number in the lower left is the atomic mass or
atomic weight, which is essentially a measurement of how heavy the element is.
5. Explain the basic subatomic
structure of elements. Tell the students that protons and neutrons reside
inside the nucleus. The electrons spin around the nucleus in what are called
orbits or shells. Each of the orbits represents a set number of electrons. For
instance, the first orbit from the nucleus has 2 electrons, the second has 8,
the third has 8, the 4th has 16 and the fifth has 32, and so on. Sodium for
instance, has 11 electrons located in the first, second, and third shells
(2+8+1.)
Elements of Metal, Non Metal,
Semi Metals
Known elements exist in the form of metals, not metals (non-metals), and semi metal.
1. Metal Elements
Metals are elements that have shiny properties and are generally good conductor of electricity and heat conductor. Metal elements are generally solid at normal temperatures and pressures, except for mercury in the form of liquid. In general, metal elements can be forged so that can be formed into other objects.
2. Non Metal Elements
The non-metallic element is an element which has no metallic properties. In general, non-metallic elements are gaseous and solid at normal temperature and pressure. Examples of non-metallic elements in the form of gases are oxygen, nitrogen, and helium. Examples of non-metallic elements in solid form are sulfur, carbon, phosphorus, and iodine. Non-metallic solids are usually hard and brittle. Non-metallic element in the form of liquid is bromine.
3. Semi Metal Elements
In addition to metal and nonmetal elements there is also a semilogam element or known as a metaloid. Metaloid is an element that has metallic and nonmetal properties. Semilogam element is usually semiconductor. What is a semiconductor? Semiconductor materials can not conduct electricity well at low temperatures, but their electrical conductivity becomes better when the temperature is higher.
Can you explain what holds an electron revolving around the nucleus? Why don't they just go zooming around everywhere?
BalasHapusWhat causes the force that holds atoms together? The answer is electricity and magnetism. The atom's center, or nucleus, is positively charged and the electrons that whirl around this nucleus are negatively charged, so they attract each other. The reason the force is strong is because the atom is so small. The distance between the nucleus and the electrons is about 1 Angstrom (named after a famous scientist); this is 0.00000001 cm (10-8 cm) or about 4 billionths of an inch. Since the electric force varies with the distance between the positive and negative charges like 1 over the distance squared, the force gets large for small distances.
HapusI would like to ask, how do you think about artificial elements?
BalasHapusBecause the elements in nature there are natural and artificial. Please explain.
synthetic elements, in chemistry, radioactive elements that were not discovered occurring in nature but as artificially produced isotopes. They are technetium (at. no. 43), which was the first element to be synthesized, promethium (at. no. 61), astatine (at. no. 85), francium (at. no. 87), and the transuranium elements (at. no. 93 and beyond in the periodic table ). Some of these elements have since been shown to exist in minute amounts in nature, usually as short-lived members of natural radioactive decay series (see radioactivity ).
HapusThe synthetic elements through at. no. 100 ( fermium ) are created by bombarding a heavy element, such as uranium or plutonium, with neutrons or alpha particles. The synthesis of the transfermium elements (elements with at. no. 101 or greater) is accomplished by the fusion of the nuclei of two lighter elements. Elements 101 through 106 were first produced by fusing the nuclei of slightly lighter elements, such as californium , with those of light elements, such as carbon . Elements 107 through 112 were first produced by fusing the nuclei of medium-weight elements, such as bismuth or lead , with those of other medium-weight elements, such as iron , nickel , or zinc . Of the elements greater than 112 whose creation has been officially confirmed, element 114 was discovered by fusing the nuclei of plutonium and calcium , and element 116 using curium and calcium.
The transfermium elements are produced in very small quantities (one atom at a time), and identification is therefore very difficult because of half-lives ranging from minutes to milliseconds and the need to identify the products by methods other than known chemical separations. This has led to controversy over reported discoveries and over the naming of the elements. It has been predicted that one isotope of element 114—containing 114 protons and 184 neutrons—would be very stable because its nucleus would have a full complement of protons and neutrons. Termed an island of stability, its half-life might be measured in years. However, none of the isotopes of element 114 synthesized as yet have as many as 184 neutrons, and their half-lives are still in the millisecond range (see flerovium ).
can you explain the elements on your blog which say that a molecule can be made up of two atoms of the same element, OR can be made up more atoms of different elements??and give examples!
BalasHapusthe matter in the universe is made of tiny particles called atoms. There are 92 different kinds of atoms in nature. These 92 different atoms combine with one another to form different kinds of matter that we see in nature.
HapusGold, for example, is made of only gold atoms. When matter is made of only one kind of atom, it is called an element. In the same way, silver is another element which is made of only silver atoms. Because there are 92 different kinds of atoms in nature, there are 92 different kinds of elements.Other examples of an atom are K (potassium) and Fe (iron).
WHAT ARE ELEMENTS?
elementThe element is the fundamental substance that consists of only one type of atom. Elements consist of smaller particles and can be man-made or synthetic. Their arrangement in the periodic table is based on the number of protons in an increasing order. The atomic number of an element is indicated by Z. When atoms are arranged differently in an element having the same number of protons, you get different forms of an element. For example, both graphite and diamond are elements of carbon but they look very different from each other.
WHAT IS A MOLECULE?
molecule-imgMolecule is the smallest unit of a chemical compound and it exhibits the same chemical properties of that specific compound. As molecules are made up of atoms jointly held by chemical bonds, they can vary greatly in terms of complexity and size.The oxygen we breathe has a molecular formula O2. Should we consider this as an element or compound?When two or more atoms of the same element combine together, we call them Molecules. So, we call O2 as an oxygen molecule. In the same way, we find hydrogen molecules H2, chlorine molecules Cl2 and others in nature.
the matter in the universe is made of tiny particles called atoms. There are 92 different kinds of atoms in nature. These 92 different atoms combine with one another to form different kinds of matter that we see in nature.
HapusGold, for example, is made of only gold atoms. When matter is made of only one kind of atom, it is called an element. In the same way, silver is another element which is made of only silver atoms. Because there are 92 different kinds of atoms in nature, there are 92 different kinds of elements.Other examples of an atom are K (potassium) and Fe (iron).
WHAT ARE ELEMENTS?
elementThe element is the fundamental substance that consists of only one type of atom. Elements consist of smaller particles and can be man-made or synthetic. Their arrangement in the periodic table is based on the number of protons in an increasing order. The atomic number of an element is indicated by Z. When atoms are arranged differently in an element having the same number of protons, you get different forms of an element. For example, both graphite and diamond are elements of carbon but they look very different from each other.
WHAT IS A MOLECULE?
molecule-imgMolecule is the smallest unit of a chemical compound and it exhibits the same chemical properties of that specific compound. As molecules are made up of atoms jointly held by chemical bonds, they can vary greatly in terms of complexity and size.The oxygen we breathe has a molecular formula O2. Should we consider this as an element or compound?When two or more atoms of the same element combine together, we call them Molecules. So, we call O2 as an oxygen molecule. In the same way, we find hydrogen molecules H2, chlorine molecules Cl2 and others in nature.
"what would you get if you combined one atom each from all the elements in the periodic table?"
BalasHapusIt wouldn't make anything really. If we combine one of each of the atoms from the periodic table, the result would be so small that we wouldn't notice it, even with the best electron microscopes. You see, some elements are very reactive and react immediately with whatever is next to it. Oxygen is a good example of that. Oxygen is extremely reactive, especially when it is in a rare single atom mode called atomic oxygen (oxygen at our level of the earth has two or three atoms). Non-reactive elements like helium, neon, argon, krypton, xenon and radon ignore all other elements and remain unchanged. So, if you were to combine one atom of each of the elements from the periodic table it would leave only a TINY group of compounds and the rest would still be sitting around as elements. Something interesting may happen on a very small scale by combining these atoms, but this depends on the orderthat the atoms are placed together.
Hapusapa sifat dari elemen?
BalasHapusHow the process of compound formation?
BalasHapusOne of the most important requirements in chemistry is to become familiar with the ways in which elements react to form compounds. We will investigate the types of chemical bonds, ways to predict compositions and the conventions of naming the compounds.
HapusChemical bonds make atoms more stable than they are if non-bonded
Bond formation involves changes in the electrons on two atoms
This is achieved by one of two methods
Electron transfer
Electron sharing
Electron transfer involves creation of ions, which bond via ionic bonds to form ionic compounds. A Familiar compound like table salt, sodium chloride, is a classic example of an ionic compound.
The documents called Type 1 Compounds and Type 2 Compounds give information on predicting composition and naming of ionic compounds[1]
Electron sharing involves the sharing of electrons between two atoms and the creation of covalent bonds. Covalently bonded compounds typically have very different properties from ionic compounds, and they also involve combinations of different types of elements.
The document called Type 3 Compounds gives information of the naming of covalent compounds.[2]
Although there are many elements and even more compounds to consider, familiarity with a few rules will greatly simplify the process of becoming conversant with determining compositions of compounds.
The octet rule
It is well known that the elements in group 8, the noble gases, are extremely unreactive. Examination of the electronic structures of these elements shows that the outer shells are full of electrons; they do not lack for electrons to fill the shells. None of the other elements has a filled outer shell.
The inference we draw from this is that the atom wants to obtain a filled shell, and this it achieves by forming bonds. This can be done by either addition of electrons or removal of electrons. The noble gas atom already has a filled shell and does not need to indulge in bonding to achieve it.
How the process of compound formation?
BalasHapuscan u explain different about, not metals (non-metals), and semi metal.?
BalasHapusElements of the periodic table are grouped as metals, metalloids or semimetals, and nonmetals. The metalloids separate the metals and nonmetals on a periodic table. Also, many periodic tables have a stair-step line on the table identifying the element groups. The line begins at boron (B) and extends down to polonium (Po). Elements to the left of the line are considered metals. Elements just to the right of the line exhibit properties of both metals and nonmetals and are termed metalloids or semimetals. Elements to the far right of the periodic table are nonmetals. The exception is hydrogen (H), the first element on the periodic table. At ordinary temperatures and pressures, hydrogen behaves as a nonmetal.
HapusPROPERTIES OF METALS
Most elements are metals. Metals exhibit the following properties:
usually solid at room temperature (mercury is an exception)
high luster (shiny)
metallic appearance
good conductors of heat and electricity
malleable (can be bent and pounded into thin sheets)
ductile (can be drawn into wire)
corrode or oxidize in air and sea water
usually dense (exceptions include lithium, potassium, and sodium)
may have a very high melting point
readily lose electrons
PROPERTIES OF METALLOIDS OR SEMIMETALS
Metalloids have some of the properties of metals and some nonmetallic characteristic.
dull or shiny
usually conduct heat and electricity, though not as well as metals
often make good semiconductors
often exist in several forms
often ductile
often malleable
may gain or lose electrons in reactions
PROPERTIES OF NONMETALS
Nonmetals exhibit very different properties from metals. Nonmetals display some or all of the following characteristics:
dull appearance
usually brittle
poor conductors of heat and electricity
usually less dense, compared to metals
usually low melting point of solids, compared with metals
tend to gain electrons in chemical reactions