Question

atomic number of an element is 17 . identify
the element write electronic configuration and mention its valency

Answer 1

We use the aufbau principle to specify the atomic configuration:

1s22s22p63s23p5

In the valence shell there are 3s2, 3px, 3py, and 3pz orbitals. One of the p orbitals is presumed to be half-filled.