Which element has duplet configuration?

Answer the following from the above information . Which element has electrons configuration of 1s^(2) 2s^(2) 2p ^(4)

Which element has electronic configuration of 1s^2 2s^2 2p^6 ?

The transition element that has stable configuration in +1 oxidation state is

Which element has no neutron ?

Which of the following element has f electro nic configuration in its + 4 state

An element has [Ar]3d ' configuration in its +2 oxidation state. Its position in the periodic table is

Which of the 2nd period elements closer to the configuration of inert gas?

Transition elements with 4s^(1) configuration are:

Element with pseudooctet configuration in its outermost shell

Which element has highest atomicity?