1. This element has 12 electrons when the atom is electrically neutral.
2. This element is an alkaline-earth metals group. It has 20 protons.
3. This element has 7 electrons when the atom is electrically neutral.
4. An isotope of this element has 8 neutrons and a mass of 14.
5. This element has a chemical symbol Hg.
6. This element belongs to the same group as aluminum (Al) and has an atomic mass of 69.72.

1. Magnesium(Mg)

2.Calcium(Ca)

3.Nitrogen(N)

4.Carbon(C)

5.Mercury(Hg)

6.Gallium(Ga)

Explanation:

1.Neutral means same no. of protons and electrons which is atomic number.So element with Atomic number 12 is Magnesium.

2. No. of protons = Atomic number.So element with Atomic number 20 is Calcium.

3.Neutral means same no. of protons and electrons which is atomic number.So element with Atomic number 7 is Nitrogen.

4.C-14 isotope has two extra neutrons making it 6+2= 8 neutrons.

5.Mercury(Hg) is the name of element.

6.Gallium(Ga) and Aluminium together belongs to Aluminium family.

pla·gia·rism

/ˈplājəˌrizəm/

learn to pronounce

noun

the practice of taking someone else's work or ideas and passing them off as one's own.

explanation:

answer is: c. the experiment shows that the red substance experienced a chemical change.

this is chemical change (chemical reaction), because two new substances are formed (metalig liquid and gas), the atoms are rearranged and the reaction is followed by an energy change.

this is example of chemical decomposition.

chemical decomposition (analysis) is the separation of a single chemical compound into its two or more elemental parts or to simpler compounds.  

chemical decomposition is opposite of chemical synthesis.