Chemistry Review – for Biology students

Big Ideas

  1. The nucleus of an atom is very (large, small) compared to the rest of the atom.
  2. The nucleus contains these two subatomic particles, ______and ______.
  3. Protons have a ______charge.
  4. Neutrons have a ______charge.
  5. The ______exist in energy levels outside of the nucleus.
  6. Electrons have a ______charge.
  7. Electrons farther away from the nucleus have (more, less) kinetic energy.
  8. Electrons that are available for bonding are called ______electrons.

Define the following terms:

Atomic Number
Average Atomic Mass
Isotope
Mass Number
Electronegativity
Atom
Ion
Element

Determining symbols, protons, neutrons, and electrons

Use the Periodic Table Distributed in Class to fill in the following charts.

Atom / Symbol / Number of Protons / Number of Neutrons / Number of electrons
Magnesium
Uranium
Lead
Tungsten

Drawing Atoms

Using the Bohr model (Planetary Model), draw the following atoms (protons, neutrons, and electrons). Below each atom write the number of valence electrons each atom has.

P
Valence electron number / K
Valence electron number / S
Valence electron number
  1. If an atom of Phosphorus was ionized, it’s new charge would be ______. It’s new symbol would be ______.
  2. If an atom of Potassium was ionized, it’s new charge would be ______. It’s new symbol would be ______.
  3. If an atom of Sulfur was ionized, it’s new charge would be ______. It’s new symbol would be ______.

In the boxes below, draw the respective ions.

O2- / N3- / Na+

Basic bonding

In biology we focus on three major types of molecular bonds. There are more, but the three we will focus on are covalent, ionic, and hydrogen.

  1. Describe what happens to the electrons in a covalent bond.
  2. Describe what happens to the electrons in an ionic bond.
  3. Describe what happens in a hydrogen bond.
  4. Draw an atom of sodium and an atom of chlorine side by side. Look at the valence electrons. How many does Na have? ______. How many does Cl have? ______What type of bond you think that these two atoms (a metal and nonmetal) form? Notice that one atom “wants to gain one” and one atom “wants to lose one”.
  1. How would you write the compound that Na and Cl form?
  1. Draw two N atoms side by side. Look at the valence electrons. How many valence electrons does each atom have? ______What type of bond do you think that these two atoms (both nonmetals) form? ______Notice that they both “want” so what will they have to do?
  1. How many electrons will each have to share? ______
  2. How would you write the chemical formula for this compound? ______
  3. How would you write the structural formula? (Hint: O2 looks like this O=O) ______

21. What is the line between these two Chlorine atoms showing? What are the pairs of dots and X’s around chlorine called?

Cl-Cl

22. Look at the skeleton structure for methane. What would be the chemical formula for methane below?