Science MCQs

The electronic configuration for Z=12 (Magnesium) is K=2 L=8 M=2. The L shell has 8 electrons.

Group 18 the noble gases have full valence shells and are very unreactive.

Argon has an atomic number (Z) of 18. Neutrons = Mass Number (40) - Z (18) = 22.

Sulfur (Z=16): K shell=2 L shell=8 M shell=6. Configuration is 2 8 6

Neon (Z=10) has configuration 2 8. 8 is twice 4? Wait check: First shell has 2. Second shell has 8. 8 is four times 2. This question is tricky. Let's find an element where L = 2*K. K is always 2 for these elements so L must be 4. Carbon (Z=6) has configuration 2 4. 4 is twice 2.

The maximum number of electrons is given by 2n². For n=4 it is 2*(4)² = 32.

Iron (Fe) is located in the block of elements from groups 3-12 which are the transition metals.

In a neutral atom the number of electrons is always equal to the number of protons (atomic number).

Elements in the same group have the same number of electrons in their outermost shell (valence electrons) which governs their chemical behavior.

Potassium (Z=19) has the electronic configuration 2 8 8 1. Its outermost shell (N) has 1 electron.