<span>B.by arranging the elements according to atomic number instead of atomic mass</span> awnser is B
Answer:
The answer is

Explanation:
The energy of a quantum of light can be found by using the formula
<h3>E = hf</h3>
where
E is the energy
f is the frequency
h is the Planck's constant which is
6.626 × 10-³⁴ Js
From the question
f = 4.31 × 10¹⁴ Hz
We have
E = 4.31 × 10¹⁴ × 6.626 × 10-³⁴
We have the final answer as

Hope this helps you
Answer:
1) magnesium chloride
2) b) The copper is getting oxidized from Cu+ to Cu2+ and turns blue.
Explanation:
The work published by David N. Frick, Sukalyani Banik, and Ryan S. Rypma in J Mol Biol. 2007 Jan 26; 365(4): 1017–1032 clearly shows that divalent metal ions of group 2 such as Mg^2+ play an important role in ATP hydrolysis. Addition of EDTA decreased the rate of hydrolysis of ATP (due to sequestration of the divalent ion of group 2) indicating an active participation of divalent ions in the process.
2) The copper I ion is colourless because it is a d^10 specie. However, when it is oxidized to Cu^2+, a blue colour appears in the solution.