Eduprobe
Question:
In the modern periodic table, calcium (atomic number 20) is surrounded by elements with atomic numbers 12, 19, 21, and 38. Which of these have physical and chemical properties resembling calcium?
Solution:
The electronic configuration of Ca(20) is 2, 8, 8, 2.
Number of valence electrons = 2
The elements with atomic numbers 12 and 38 both have 2 valence electrons in their outer shell, but elements with 19 has 1 valence electron and 21 has 3 valence electrons. Therefore, elements with atomic numbers 12 and 38 have physical and chemical properties resembling calcium.