Question

PLEASE ANSWER WITH EXPLAINATION ​

Answer 1

Answer:

a.)y(nitrogen) and z(fluorine).

b.)metal

c.)fluorine

Explanation:

at. mass. at.number. element

x. 40. 20. calcium

y. 14. 7. nitrogen

z. 19. 9. fluorine

a.) nitrogen and fluorine both belongs to 2 period as there valence electron enter in 2 shell .

b.) calcium is metal because it enter in group 2 ( alkani earth metal).

• c.) as we going across the period the atomic size decrease because of increasing the effective nuclear charge and the shielding effect remain constant which tends to pull the electrons closer which make the atom smaller.