Answer:
atomic number of Be =4
electronic configuration :1s²2s²
but for Be2+ atomic number = 4-2 =2
electronic configuration : 1s²
Answer:
The first one is air the second is decreases the third is water the fourth is gas and the last is liquid.
Explanation:
Hope it helps.
#2 onshahebsisbunwubsydtebwownsddhiiw
Alpha particles because two protons and two neutrons
