Group names in the periodic table give clues about the metallic properties of the elements. 
Metallic elements are found on the left side of the periodic table. A simple conception of metals describes them as a lattice of positive ions immersed in a sea of electrons.
        
             
        
        
        
Answer:
What is a Metal ? Metals. Metals are opaque, lustrous elements that are good conductors of heat and electricity. Most metals are malleable and ductile and are, in general, denser than the other elemental substances.
Explanation:
Metalloid, in chemistry, an imprecise term used to describe a chemical element that forms a simple substance having properties intermediate between those of a typical metal and a typical nonmetal. ... 
Definition: The non-metals are elements on the right of the periodic table
 
        
             
        
        
        
Answer:

Explanation:
                   2NO₂ ⇌ N₂O₄
E/mol·L⁻¹:   0.058     0.012
K_{\text{eq}} = \dfrac{\text{[N$_{2}$O$_{4}$]}}{\text{[NO$_{2}$]$^{2}$}} = \dfrac{0.012}{0.058^{2}} = \mathbf{3.6}
\\\\
\text{The $K_{\text{eq}}$ value would be $\boxed{\mathbf{3.6}}$}
 
        
             
        
        
        
Answer:
Oxygen
Explanation:
I'm not completely sure about the explosion part but I know oxygen fuels fire.