Characteristics of an Atom
Every atom of a specific element will always have the same number of protons and always have the same number of electrons. The number of neutrons in atoms of an element can change. There are several ways to characterize atoms, based on the number of protons and neutrons they contain. Atomic number: Number of protons in an atom of an element - determines what element the atom belongs to.
Example:
Mass number: Total mass number of protons + neutrons.
Example:
Isotopes : Atoms of an element with different # of neutrons. Isotopes of an element have the same chemical properties. Radioisotopes are unstable isotopes that emit energy (radiation).
Example:
Atomic mass (atomic weight): The atomic mass of an element is the average mass of all its naturally occurring isotopes.
2) Element: are composed of atoms of the same type.
Elements are substances that cannot be divided into simpler substances by chemical means There are 92 naturally occurring elements Each of the elements has been named and given a symbol and has been arranged in the periodic table of the elements
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