Answer:
mass number
Explanation:
When there is an element name followed by a dash and then a number, the number simply represents the mass number.
for example:
Oxygen- 18
18 represents the mass number of this particular isotope
Answer:
The "right" answer is 4. When matter is a gas, the particles flow freely, having no fixed shape or volume and contain a lot of extra space between particles.
However the last part, "...with a lot of empty space between them giving it energy" is (I'm fairly certain) incorrect. The relationship is the other way. Energy is added to the system, causing the particles to move more, thus building up the space between them.
The Lewis dot diagram structure for hydrogen cyanide would be the following:
H - C --- N
--- = triple bond.
