Question

define
(a)valency
(b)atomic number
(c)mass number​

Answer 1

Answer:

1 = In chemistry, the valence or valency of an element is the measure of its combining capacity with other atoms when it forms chemical compounds or molecules

2 = Atomic number, the number of a chemical element in the periodic system, whereby the elements are arranged in order of increasing number of protons in the nucleus. Accordingly, the number of protons, which is always equal to the number of electrons in the neutral atom, is also the atomic number.

3 = The mass number, also called atomic mass number or nucleon number, is the total number of protons and neutrons in an atomic nucleus. It is approximately equal to the atomic mass of the atom expressed in atomic mass units

Answer 2

Answer:

1) valency of an element is the combining capacity of the element which other elements and it is equal to the number of electrons that take part in a chemical reaction