Use the periodic table to determine the electron configuration for aluminum (al) and arsenic (as) in noble-gas notation.

Electronic configuration of

1. Aluminium is

2. Arsenic is

Explanation: To write the electronic configuration of the elements in the noble gas notation, we first count the total number of electrons and then write the noble gas which lies before the same element.

Atomic number = 13

Total number of electrons = 13

Noble gas which lies before this element is Neon (Ne).

Neon has 10 electrons, rest 3 electrons are filled in 3s and 3p sub-shells.

Electronic configuration of Aluminium becomes

Atomic number = 33

Total number of electrons = 33

Noble gas which lies before this element is Argon (Ar).

Neon has 18 electrons, rest 15 electrons are filled in 4s , 3d and 4p sub-shells.

Electronic configuration of Arsenic becomes .

it means there are 3 atoms of oxygen

there is none because earth is stationary and flat.