The atomic number of copper is 29.
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Elements in the same group have D. Same number of valence electrons.
Answer: The mole ratio of sodium to sodium chloride 2:2.
Explanation:
As the given reaction equation is as follows.

Here, 2 moles of sodium reacts with 1 mole of
and leads to the formation of 2 moles of NaCl.
This means that 2 moles of sodium gives 2 moles of NaCl on reaction with chlorine.
Hence, the ratio of moles of sodium to sodium chloride is 2:2.
Thus, we can conclude that the mole ratio of sodium to sodium chloride 2:2.
Answer:
I will say D. The molecules become arranged into regular cubic arrangement. but i'm not 100% sure
Explanation:
They have less or more neutrons. Isotopes have same number of protons but different number of neutrons.