Electron configuration for lithium.

The answer to problem is [He] 2s1. Hope it helps

Your answer is [He] 2s1

Hope that helps :)

the density(ratio between mass and volume as m/v) decreases from top to bottom in periodic table group as the size increases and nuclear charge decreases. but in periods density increases from left to right as atom size decreases and nuclear charge increases.

the answer is true. hope it .