For the First part I believe elements naturally exist in nature and compounds are formed so elements can be more stable. (I think this is right I’m not 100% but I’m close)
For the second part the two main types of bonds are ionic and covalent. Ionic bonds involve the transfer of electrons and covalent bonds involve the sharing of electrons. (I’m 100% on this one)
Answer is:
1: Kr.
2: Cl₂.
3: F₂.
4: O₂.
5: N₂.
6: He.
The lighter (smaller) particles move more quickly than heavier (larger) ones at the same temperature.
Calculate molar masses of the compounds:
M(Cl₂) = 70.9 g/mol; molar mass of chlorine gas.
M(F₂) = 38 g/mol, molar mass of fluorine gas.
M(He) = 4.002 g/mol; molar mass of helium.
M(Kr) = 83.8 g/mol; molar mass of krypton.
M(N₂) = 28.01 g/mol; molar mass of nitrogen gas.
M(O₂) = 32 g/mol; molar mass of oxygen gas.