An atom is constructed of three major
particles; two of them are in a central region or core called the
atomic nucleus. The third type of particle is in the region surrounding
the nucleus. The weight or mass of the atom is concentrated in the
nucleus. The nucleus of the atom contains the protons and the neutrons,
which are the massive particles of the atom. One type of particle
located in the nucleus is the neutron.
Identity of the element
All the atoms of the same element have the same number of protons. The number of protons determine the identity of the element. For example, carbon always has 6 protons and no other element has that number. Oxygen always has 8 protons. The atomic number of an element is the number of protons in an atom of that element; therefore, each element has a unique atomic number. Because this is an extremely small mass and is awkward to express, 1 proton is said to have a mass of 1 atomic mass unit.
Neutral atoms
Although all the neutral atoms of the same element have the same number of protons and electrons, they do not always have the same number of neutrons. In the case of oxygen, over 99% of the atoms have 8 neutrons, but there are others with more or fewer neutrons. Each atom of the same element with a different number of neutrons is called an isotope of that element. Since neutrons have a mass very similar to that of a proton, isotopes that have more neutrons will have a greater mass than those that have fewer neutrons.
Isotopes
Elements occur in nature as a mixture of isotopes. The atomic weight of an element is an average of all the isotopes present in their normal proportions. For example, of all the isotopes present in their normal proportions. For example, of all the hydrogen isotopes on Earth, 99.985% occur as an isotope without a neutron and 0.015% as the isotope with one neutron.There is a third isotope with two neutrons but it is not considered because it is highly unstable. When the math is done to account for the relative amounts of the various isotopes of hydrogen, the atomic weight turns out to be 1.0079 AMU.
Mass number of an atom
The sum of the number of protons and neutrons in the nucleus of an atom is called the mass number. Mass numbers are used to identify isotopes. A hydrogen atom with 1 proton and 1 neutron has a mass number of 1 + 1, or 2, and is reffered to as hydrogen-2 ( also called deuterium). A hydrogen atom with 1 proton and 2 neutrons has a mass number of 1 + 2 , or 3, and is referred to as hydrogen-3 ( also called tritium).
Introduction
Neutrons were named to reflect their lack of electrical charge. They are neutral. Protons, the second type of particle in the nucleus in certain areas called enegry levels are the electrons. Each electron has a negative electrical charge. The number of electrons determine the space that an atom occupies.Charge of an atom
The charge of an atom is neutral if the number of positively charged protons equals the number of negatively charged electrons. For instance, hydrogen with 1 proton, would have 1 electron; carbon with 6 protons would have 6 electrons. You can determine the number of either of these two particles in a neutral atom if you know the number of other particles.Identity of the element
All the atoms of the same element have the same number of protons. The number of protons determine the identity of the element. For example, carbon always has 6 protons and no other element has that number. Oxygen always has 8 protons. The atomic number of an element is the number of protons in an atom of that element; therefore, each element has a unique atomic number. Because this is an extremely small mass and is awkward to express, 1 proton is said to have a mass of 1 atomic mass unit.
Neutral atoms
Although all the neutral atoms of the same element have the same number of protons and electrons, they do not always have the same number of neutrons. In the case of oxygen, over 99% of the atoms have 8 neutrons, but there are others with more or fewer neutrons. Each atom of the same element with a different number of neutrons is called an isotope of that element. Since neutrons have a mass very similar to that of a proton, isotopes that have more neutrons will have a greater mass than those that have fewer neutrons.
Isotopes
Elements occur in nature as a mixture of isotopes. The atomic weight of an element is an average of all the isotopes present in their normal proportions. For example, of all the isotopes present in their normal proportions. For example, of all the hydrogen isotopes on Earth, 99.985% occur as an isotope without a neutron and 0.015% as the isotope with one neutron.There is a third isotope with two neutrons but it is not considered because it is highly unstable. When the math is done to account for the relative amounts of the various isotopes of hydrogen, the atomic weight turns out to be 1.0079 AMU.
Mass number of an atom
The sum of the number of protons and neutrons in the nucleus of an atom is called the mass number. Mass numbers are used to identify isotopes. A hydrogen atom with 1 proton and 1 neutron has a mass number of 1 + 1, or 2, and is reffered to as hydrogen-2 ( also called deuterium). A hydrogen atom with 1 proton and 2 neutrons has a mass number of 1 + 2 , or 3, and is referred to as hydrogen-3 ( also called tritium).
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