Answer:

Explanation:
Hello,
The six-carbon benzene ring contains two types of bonds: C-C and C-H bonds, that are
-hybridized σ bonds, and the six π bonds that form the aromatic ring. The σ bonds form from one
orbital and two
orbitals from each carbon, which then bond the carbon to the two carbons on either side and the carbon's single hydrogen. The remaining
orbital from each carbon atom sticks out above and below the plane of the ring; these
orbitals overlap sideways, rather than lengthwise, to form the aromatic π bond system.
Best regards.
Frequency = velocity (aka speed) / wave length
The negative ion reactions that consist of the formation of carbon dioxide in the atmosphere is generally an exothermic reaction. By definition, an exothermic reaction takes place when the chemical process eventually releases heat as its by-product. It is in contrast in endothermic process wherein heat is absorbed.
ANSWER:
4 a) Specific elements have more than one oxidation state, demonstrating variable valency.
For example, the following transition metals demonstrate varied valence states:
,
,
, etc.
Normal metals such as
also show variable valencies. Certain non-metals are also found to show more than one valence state 
4 b) Isotopes are members of a family of an element that all have the same number of protons but different numbers of neutrons.
For example, Carbon-14 is a naturally occurring radioactive isotope of carbon, having six protons and eight neutrons in the nucleus. However, C-14 does not last forever and there will come a time when it loses its extra neutrons and becomes Carbon-12.
5 a)
→
5 b)
→ 
5 c)
→
(already balanced so don't need to change)
5 d)
→
5 e)
→ 
EXPLANATION (IF NEEDED):
1. Write out how many atoms of each element is on the left (reactant side) and right (product side) of the arrow.
2. Start multiplying each side accordingly to try to get atoms of the elements on both sides equal.
EXAMPLE OF BALANCING:
Answer:
1.1 mol
Explanation:
n=m/M, where n is moles, m is mass, and M is molar mass.
M of CO2 = 12.01+16.00+16.00 = 44.01g/mol
n=50g/44.01g/mol
n = 1.13610543 mol
n ≈ 1.1 mol
Hope that helps