How does the current level of atmospheric co2 compare to historic levels?

Well, currently CO2 levels have been increased. The concentration of this gas has not stopped increasing since the beginning of the sixties, when the records of this gas began to be made.

Explanation:

The atmospheric concentration of CO2 has reached 415 parts per million, passing the 400 barrier, which was exceeded in 2015, the crucial year where the Paris Agreement was signed. This agreement seeks to reduce greenhouse gases whose purpose is to avoid an increase in temperature. The current concentration of carbon dioxide is 145% of the industrial levels, very high levels in the atmosphere for this gas.

atomic mass = 39

number of neutrons = 20

number of protons= 19

electronic configuration = 1s2 2s2 2p6 3s2 3p6 4s1

the number of electron in first shell = 2

number of electrons in n=3 shell = 8