Answer:
A
Explanation:
Lanthanides share the following common properties: Silvery-white metals that tarnish when exposed to air, forming their oxides. Relatively soft metals. Hardness increases somewhat with higher atomic number.
Answer:An oxygen atom usually has 8 protons, 8 neutrons, and 8 electrons. Looking at the periodic table, oxygen has atomic number 8 and atomic weight 15.999.
Explanation:
Because the sublevels 1s only has one shape ,and it only contains 2 elections...
