Question

How would you rank the following elements in order of decreasing atomic number: $F,O,C,B$?

Answer 1

Atomic number and mass number are always whole numbers because these are obtained by counting the number of protons, electrons and neutrons which are whole in nature. The sum of the mass number and the atomic number for an atom corresponds to the total number of subatomic particles present in the atom.

Complete step by step answer:
Atom is composed of a nucleus which is made up of protons and neutrons where protons are positively charged ions and neutrons are neutral in nature i.e. carries no charge and electrons are revolving around the nucleus.
Atomic number is represented by the symbol Z which can be calculated by the total number of protons present in the nucleus. All the atoms of a particular element have the same number of protons which define that it has the same atomic number and atoms of different elements have different atomic numbers. Modern periodic table is arranged in the manner of increasing atomic number.
Atomic number of $F$ is 9 known by the name fluorine, atomic number of $O$ i.e. oxygen is 8, atomic number of $C$ known by the name carbon is 6 and atomic number of $B$ i.e. boron is 5.
**Hence atomic number is decreasing in the order of $B

Note: Atomic number is given by the number of protons present in the nucleus of an atom and this term was discovered by Henry Gwyn-Jefferies Moseley and it is represented by the symbol Z where Z stands for Zahl which is German word meaning number.