What element is represented by 1s22s22p63s23p64s5

                  Calcium

                          The position of an element in representative blocks of periodic table can be located by finding out its valence shell and the number of valence electrons present in that particular valence shell.

The electronic configuration given is as follow,

                                    1s², 2s², 2p⁶, 3s², 3p⁶, 4s²

Remember than the s orbital can accomodate the maximum of 2 electrons hence, the 5 can be ignored.

As the valence shell is 4 it means that the element is present in period 4 and the number of electrons in shell 4 are two hence, the group number is 2.

On inspecting group 2 and period 4 we found that the element is Calcium.

answer

i think the answer is a) as air pressure in an area increases, the density of the gas particles in that area decreases.

hope it