Consider these elements: p, ca, si, s, ga. a. write the electron configuration for each element

Method:

1) Find the atomic number in a periodic table: the number of electrons equal the atomic number

2) Use Aufbau rule

Element     atomic number       electron configuration

P                15                            1s2 2s2 2p6 3s2 3p3

Ca              20                            1s2 2s2 2p6 3s2 3p6 4s2

Si                14                            1s2 2s2 2p6 3s2 3p2

S                 16                            1s2 2s2 2p6 3s2 3p4

Ga               31.                           1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p