Question

an element X has mass number 35 and number of neutrons 18. write atomic number and electronic configuration of "X". also write group number period number and valency of" X". write the formula of compound formed when" X "reacts with hydrogen

Answer 1

Mass number = number of protons + number of neutrons

Number of protons = mass number - number of neutrons

= 17

Atomic number = number of protons

= 17

Electronic configuration = 2(k), 8(l), 7(m)

Group number = 17

Period number = 3

Valency = -1

When X reacts with hydrogen it gives HCl (Hydrochloric acid)

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