Question

1. How many periods are there in the periodic table? *

Answer 1

The periodic Table has 7 periods and 18 groups. The number of valence electrons in an atom of sulfur is 6, calcium has 2, chlorine has 7 and arsenic has 5. The element that corresponds to the atomic number 10 is Neon, for 18 it is argon, for 36 it is krypton, and for 90 it is thorium. Na and CI belong to the same period, as does H and He. An element found in period 4 would have 4 energy levels. The transition elements are in groups 3-12. Strontium would be more chemically similar to calcium, because they are both in the same family/group. The heaviest noble gas is radon. The heaviest alkaline earth metal is radium.