Only oxygen, hydrogen, nitrogen, fluorine, and chlorine can bond with itself to form gas. Noble gases, elements in the last column, do not bond with themselves to be able to form gas molecules since their valence shells have full octets of electrons.

To find the number of neutrons take the atomic mass of each element and subtract it by the atomic number. For neon this is:

Elements on the right section of the periodic table are non-metals. The first two columns of the periodic table are the alkali metals and the alkaline earth metals, respectively. Groups 3-12 are the transition metals (except the lanthanide and actinide series). The "stairway" from the top left of the p-block to the bottom right of the p-block are the metalloids, which include boron, silicon, germanium, arsenic, antimony, tellurium, and polonium. The remainder of the elements are nonmetals, which include the halogens and noble gasses in groups 7 and 8, respectively.

Alkali metals are extremely reactive with water. Metals are generally shiny and good conductors of electricity. Noble gases are all gases. Halogens are mostly gases or liquids. Non-metals, however, are generally solid, dull, brittle, not conductive of electricity, and not reactive with water.

This is a knowledge based question. The incorrect answers are all true facts about Halogens. Halogens are very reactive because they have seven electrons in their outer shell. Atoms that are closer to achieving the Octet rule are more reactive. 

The correct answer is hydrogen. While it's misleading that hydrogen is located on the left hand side of the periodic table with the rest of the metals, it is actually not characterized as a metal. The main reason why hydrogen is listed as a group 1 element is due to its electron configuration. 

Hydrogen would not be considered a metal due to the following reasons:

1. It will not readily form cations as the rest of the group 1 elements.

2. When in its elemental form, hydrogen is in its diatomic stage as . This is also seen with elements such as nitrogen and oxygen, which are also nonmetals. 

3. It will form covalent bonds, unlike metals. Metals are known to commonly form ionic bonds.

4. It will form hydride ions. It is extremely rare to see group one elements do the same. 

This problem is one that can be quickly answered by looking at a periodic table of the elements. Carbon, nitrogen, oxygen, phosphorus, sulfur, selenium are all nonmetals. The other options are incorrect as they reference other classes of elements. 

Groups 3 to 12 on the periodic table contain all of the transition metals. Any elements found outside of these groups is not a transition metal. Transition metals have a partial amount of the d subshell filled with electrons. 

Noble gases are naturally occurring elements that already have eight electrons in their outer shell. Chemical reactions typically occur because atoms are following the octet rule. Since noble gases already have eight electrons in the outer shell, they are less likely to react. 

Transition metals are unique because they have valence electrons in different shells. Transition metals have several different oxidation states and can react in a variety of ways because of how their valence electrons are arranged. All alkali only have one valence electron.