Question

an element is represented as mass number 40 and atomic number twenty and symbol of element A
(a) what is its atomic number
(b) what is its mass number
(c) what is the number of protons in its nucleus

(d) what is the number of electrons in its atom
(e) what is the number of neutrons in its nucleus
(f) what is its valency​

Answer 1

Answer:

(a) 20

(b) 40

(c) 20

(d) 20

(e) 20

(f) valency=5 (not sure)

....hope this helps u....