Question

An elemebt 'x' has mass number 35 and number of neutrons 18. Write atomic number and electronic configaration of 'x'. Also write group number ,period and valency of 'x'

Answer 1

Atomic number = number of protons
Number of protons = mass number - number of neutrons
= 35 - 18
= 17
For electronic configuration
Number of protons = number of electrons
Number of electrons = 17
So EC is
K L M
2 8 7
Its valency is 1
Its period number is 3
Its group number is 1 .