Design techniques and materials that reduce the negative environmental impact of a structure are referred to as

1.solid

2.carbon dioxide

3.helium

1.43 x 10^-11 j the guy commented the awnser just making sure u see it .

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