Name ______Date ______

CP Biology

Chapter 2 Study Guide – The Chemistry of Life

(What’s the MATTER…need a little review of chemistry?) 

Read pages 34 – 38 in your textbook (Section 2.1) and review the following terms below, then complete the attached worksheets.

Both living and nonliving things are composed of MATTER – anything that takes up space and has mass.

TheAtom is the basic unit of matter, made up of three subatomic particles:

  • Protons have a positive charge and neutrons carry no charge. Strong forces bindprotons and neutrons together in the nucleus.
  • An electronis a negatively charged particle that has only about 1/1840 the mass of aproton. Electrons constantly move around the space surrounding the atom’s nucleus (“electron cloud”).
  • Valence electrons are found in the outer most energy level. Valance electrons determine the CHEMICAL PROPERTIES of an atom. (Atoms with filled valence energy levels are nonreactive, and will not bond with other atoms.)
  • Because an atom has the same number of protons and electrons, if it is electrically neutral.

A chemical element is a pure substance that consists entirely of one type of atom.

Isotopes are atoms of the same element that differ in the number of neutrons. Isotopes are identified by their mass number, the total number of protons and neutrons in the nucleus. Because they have the same number of electrons in each atom, all isotopes of an element have the same chemical properties.

A chemical compound is a substance formed by the chemical combination of two or more elements in definite proportions. The physical and chemical properties of a compound are usually very different from those of the elements from which it is formed.

Scientists use formulas to show the ratio of elements that make up a compound:

Chemical formula - Shows the numbertype of atoms in a compound

Structural formula - Shows the numbertypeof atoms& its structure

Chemical Bondsare forces of attraction between 2 atoms that hold them together. Only valance electrons are available to bond, thus giving atoms their chemical properties.

  • An ionic bond forms when one or more electrons are transferred from one atom to another, forming ions.This occurs between a metal and a nonmetal. An atom that loses electrons becomes positively charged (cation).An atom that gains electrons becomes negatively charged (anion).
  • A covalent bond forms when electrons are shared rather than transferred. The structure formed by atoms joined by covalent bonds is called a molecule.Covalent bonds form between nonmetals.

More Chemistry Review!

(Yes, I’m sure you learned this already.)

Atomic Number = # of ______

MassNumber= # of ______+ # of ______

Below are the 4 chemical elements that are most abundant in living matter.

Use a periodic table to help you complete the table.

Element Symbol / Element Name / Atomic Number / Atomic Mass / # of Protons / # of Electrons / # of Neutrons / # of Valence electrons / Net charge
on atom
C
O
H
N

Use the clues and words to help you write the vocabulary terms from the chapter in the blanks. You may use a word once or not at all.

  1. Substances made up of only one kind of atom are called ______. Substances made up of two or more atoms that are combined in a definite ratio are known as ______.
  2. Each atom has a central part called the ______. Inside this central part are positively charged ______and neutral______. In the space outside the central part are tiny, negatively charged ______.
  3. Atoms that are ______emit protons and energy from the nucleus.
  4. the substance formed when covalent bonds unite atoms______
  5. an atom that has gained or lost an electron ______
  6. an atom of the same element that differs in the number of neutrons ______

Answer the following questions.

  1. Give 2 examples of ionic compounds and 2 examples of covalent compounds.

2. Complete the table below.

Covalent bonds can be shown with a line connecting the atoms.

The line indicates the sharing of 2 electrons.

Structural
Formula / Chemical Formula / Chemical Name / Type of Bond
(single, double, or
triple covalent bond?Polar or nonpolar?) / # of e- shared
O
H H
Carbon dioxide
N N
  1. The chart below shows the three isotopes of carbon.

An isotope is______.

Apply what you know about isotopes to fill in the blank cells.

Isotopes of Carbon

Isotope

/ Number of Protons / Number of Electrons / Number of Neutrons
Carbon–12 (nonradioactive) / 6
Carbon–13 (nonradioactive) / 6 / 6
Carbon–14
(radioactive)

3. What’s RADIOISOTOPE?

Balance the following chemical equations.

1. KClO3 KCl + O2

2. Al + O2 Al2O3

3. K + Zn3(PO4)2 Zn + K3PO4

4. HCl + NaOH H2O + NaCl

5. C6H12O6 + O2 CO2 + H2O