What is the electron configuration for 1s22s22p63s23p64s2?

Answer 1

I believe its Boron.1s2 2s2 2p1 --> 5 electrons. Boron is atomic number 5, so 5 protons and 5 electrons balance. Look at the Periodic Table. The first row (period) corresponds to the first level of electron shell (1s). The second row corresponds to the second shell (2s & 2p). Shell 2s is Lithium and Beryllium on the far left, then 2p for the groups (columns) on the right hand side. It 'jumps' with a gap, because lower shells fill up faster (2p has a maximum of 6 electrons, which when full is Neon - a noble gas will a full shell)

Answer 2

The element calcium (with atomic number 20) has the mentioned electronic configuration

Answer 3

The given element has 5 overall electrons, so it should be Boron.

Answer 4

Oxygen.

Answer 5

Neon