Answer:
A. 28 years
Explanation:
Applying,
R = R'(2ᵃ/ⁿ).............. Equation 1
Where R = Original sample, R' = Sample left after decay, a = Total time taken to decay, n = half life.
From the question,
Given: R = 12 g, R' = 6 g, a = 28 years.
Substitute into equation 1 and solve for n
12 = 6(2²⁸/ⁿ)
12/6 = 2²⁸/ⁿ
2²⁸/ⁿ = 2
Equation the base,
28/n = 1
n = 28 years.
Hence the half-life is 28 years
Answer: The average valence electron energy (AVEE) of this element =
1014.2 KJ/ mol or 1.0142mJ/mol.
Explanation:
The average valence electron energy = (number of electrons in s subshell x Ionization energy of that subshell) + (number of electrons in p subshell x Ionization energy of that subshell) / total number of electrons in both subshells of the valence shells.
The 5A elements are non-metals like Nitrogen and Phosphorus with the metallic character increasing as you go down the group, So a new 5A element will have characteristics of its group with 5 valence electron in its outermost shell represented as ns2 np3
Therefore the average valence electron energy (AVEE) of this element will be calculated as
The average valence electron energy = (2 x 1370 kJ/mol + 3 x 777 kJ/mol.) / 5
2740+2331/ 5 =5071/5
=1014.2 KJ/ mol or 1.0142mJ/mol.
Jupiter, Saturn, Uranus, Neptune, Jovian... is your answer.
