Answer:
Most radio waves have wavelengths between 1 mm and 100 km.
A cooling curve shows A. how the temperature of a substance falls as heat is removed.
Explanation:
<em>Radio waves</em> are the longest of all the waves in the electromagnetic spectrum.
Most have wavelengths between 1 mm and 100 km, although there is no upper limit.
Some radio waves have wavelengths of 10 000 km.
A <em>cooling curve</em> (see image below) shows how the temperature of a substance falls as it is cooled.
In Option E., a decrease in temperature would cause an energy <em>loss</em>.
Options B., C., and D. involve the <em>addition of heat</em>.
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:
The correct answer is Gamma decay. It happens after beta and alpha decay
because what's left after those two can enter a new process of gamma
decay. This releases gamma rays which is a more complex term for the
photons that you mentioned before. These rays can be dangerous for
humans so care not to get caught in them.
Answer:
Hydrogen and Cobalt
Explanation:
Break up each individual element
- Hope that helps! Please let me know if you need further explanation.
Answer:
In ionic bonding, atoms transfer electrons to each other. Ionic bonds require at least one electron donor and one electron acceptor. In contrast, atoms with the same electronegativity share electrons in covalent bonds, because neither atom preferentially attracts or repels the shared electrons.