Atomic Mass, Number; Isotopes

Question 0

Atomic number

Answer 0

The atomic number is composed of the total nuclear charge, or the number of protons in the nucleus of the atom.

The atomic number is also the number of electrons surrounding the nucleus of a neutral atom.

The atomic number is the smaller of the two numbers that exist for each element on the periodic table.

Question 1

Atomic mass

Answer 1

The mass of an atom consists of the cumulative mass of all the particles in the atom- protons, neutrons, electrons.

The mass of the electrons is insignificant relative to the mass of protons and neutrons. Therefore, the atomic mass is calculated by adding up the masses of the protons and neutrons.

Question 2

Isotopes

Answer 2

Atoms with the same number of protons but with different numbers of neutrons are isotopes of one another.

Question 3

Average mass number

Answer 3

In nature, elements naturally occur as a combination of more that one isotope.

The average mass number takes into account the relative frequencies of the different isotopes.

The average mass number is also called the atomic weight.

This number is also the molar mass of the element, or the mass in grams of one mole of atoms. 6.02•10(to the 23) atoms constitutes one mole of atoms.

This is the larger number that exists on the periodic table of elements.

The atomic weight is probably closest in value to the most commonly existing isotope.