Sample Questions

Questions:

1. What is the nucleus of an atom made up of?
2. Explain why atoms that are arranged in the same vertical grouping of the periodic table have similar chemical properties.
3. Explain why Carbon is more likely to form covalent bonds with other atoms as opposed to forming an ionic molecule.
4. Explain why covalent bonds are better suited than ionic interactions to hold molecules of your body together. 
5. How many cars are in a mole of cars?
6. Describe, in detail, the formation of the ionic compound LiF.

Answers:

1. The nucleus of an atom is made up of protons and neutrons.
2. Atoms arranged in the same vertical grouping of the periodical table have similar chemical properties because they all have the same number of valence electrons.  The electrons are what reacts. 
3. Because carbon has four valence electrons, they have more energy and it is more difficult for other atoms to 'steal' four electrons.  Instead, carbon 'shares' its electrons to become stable. 
4. Covalent bonds are better to hold molecules of your body together because there can be long strands of covalent bonds which are strong, especially for holding important life functions of the body together.  Covalent bonds aren't broken by hydrogen bonds. 
5. There are 6.02 x 10²³ cars in a mole of cars.
6. In the ionic compound LiF, neither of the atoms are stable on their own.  Li needs to lose an electron to be stable, and F needs to gain one to be stable.  The electrons attract, and Li gives up his valence electrons to F.  Li loses electrons and becomes positive, F gains electrons and becomes negative.  Opposites attract.  Therefore, they both become stable.