Name: ______Date: ______

Review: Atoms

  1. The 3 particles of the atom are:

a. ______b. ______c. ______

  1. Their respective charges are:

a. ______b. ______c. ______

  1. The number of protons in one atom of an element determines the atom’s ______, and the number of electrons determines its ______.
  2. The atomic number tells you the number of ______in one atom of an element. It also tells you the number of ______in a neutral atom of that element. The atomic number gives the “______“of an element as well as its location on the Periodic Table. No two different elements will have the ______atomic number.
  3. The ______of an element is the average mass of an element’s naturally occurring atoms, or isotopes, taking into account the ______of each isotope.
  4. The ______of an element is the total number of protons and neutrons in the ______of the atom.
  5. The mass number is used to calculate the number of ______in one atom of an element. In order to calculate the number of neutrons you must subtract the ______from the ______.
  6. Give the symbol and number of protons in one atom of:

Lithium ______Bromine ______Iron ______

Copper ______Oxygen ______Mercury ______

Krypton ______Helium ______

  1. Give the symbol and number of electrons in a neutral atom of:

Uranium ______Chlorine ______Boron ______

Iodine ______Antimony ______Xenon ______

  1. Give the symbol and number of neutrons in one atom of:

(To get “mass number”, you must round the “atomic mass” to the nearest whole number)

Barium ______Bismuth ______Carbon ______

Hydrogen ______Fluorine ______Magnesium ______

Europium ______Mercury ______

  1. Name the element which has the following numbers of particles:

a. 26 electrons, 29 neutrons, 26 protons ______

b. 53 protons, 74 neutrons ______

c. 2 electrons (neutral atoms) ______

d. 20 protons ______

e. 0 neutrons ______

  1. At a minimum, what information must you have to determine the identity of an element? ______

A typical isotopic symbol takes this form: X

Where: X = element symbol; A = mass number [# of protons (p) + # neutrons (n)];

Z = atomic number [# of protons]; N = # of neutrons; A – Z = N

  1. In a neutral atom, # Protons = # Electrons: True or False?
  2. Thallium (Tl) has two isotopes: thallium-203 and thallium-205. Thallium's atomic number is 81, and its atomic mass is 204.38 amu. Which statement about the thallium isotopes is true?

a. There is more Tl-203 in nature c. Tl-205 atoms have fewer neutrons

b. Atoms of both isotopes have 81 protons d. The mass of the most common Tlatom = 204.38 amu.

  1. Atoms consist of: (circle all that apply) Protons NeutronsMoleculesElectrons
  2. Which of these descriptions is incorrect?

Proton: positive charge, in nucleus, mass of = 1 amu

Electron: negative charge, mass of = 0 amu, in nucleus

Neutron: mass of = 1 amu, no charge

  1. The atom that has atomic mass of 12 has ______protons.

123456128

  1. What do you call an atom that is positively or negatively charged because it gained or lost one or more electrons? ______
  2. The valence electron(s) is/are theoutermostelectron(s) in an atom.
  3. The center of an atom is called the: ______
  4. In an atom, the ______form a cloud around the nucleus.
  5. Objects that are electrically neutral, become______charged when they gain electrons.
  6. In an element with a neutral charge, the atomic number is equal to the number of ______
  7. ______are particles with no charge. Protons Neutrons Electrons
  8. ______are negatively charged particles. ProtonsNeutronsElectrons
  9. ______are positively charged particles.ProtonsNeutronsElectrons
  10. The atom has the following parts ______
  11. What charge do protons carry? ______
  12. Is an atom the smallest particle of matter?True False
  13. Determine the average atomic mass of this mixture of naturally occurring isotopes of Barium.

Isotope / N.A.% / amu
Ba - / 130 / 0.106% / ______
Ba - / 132 / 0.101% / ______
Ba - / 134 / 2.417% / ______
Ba - / 135 / 6.592% / ______
Ba - / 136 / 7.854% / ______
Ba - / 137 / 11.23% / ______
Ba - / 138 / 71.7%
Sum =
  1. Some possible sources of experimental error are:

Inaccurate measurements; flawed methodology; poor experimental design; careless practices; inadequate or inferior tools; unforeseen circumstances or occurrences