Question

Write the atomi no of the element in the third period and seventh group of the periodic table

Answer 1

Answer:

element chlorine

atomic number - 17

atomic mass - 35.5

Answer 2

Answer:

Explanation:

There are two elements in the 1st period and eight elements in the 2nd period., The third period starts with the element with Z = 11(sodium). ... Hence, the element in the 17th group of the third period has atomic number Z = 17 ,chlorine(Cl)