Review: Atoms

Name: ____Mr. John______Date: ____KEY______

  1. The 3 particles of the atom are:

a. protonb. neutronc. electron

  1. Their respective charges are:

a. positiveb. neutralc. negative

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

Lithium Li, 3______Bromine Br, 35______Iron Fe, 26______

Copper Cu, 29______Oxygen O, 8______Mercury Hg, 80______

Krypton Kr, 36______Helium He, 2______

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

Uranium U, 92______Chlorine Cl, 17______Boron B, 5______

Iodine I, 53______Antimony Sb, 51______Xenon Xe, 54______

  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 Ba, 81______Bismuth Bi, 126______Carbon C, 6______

Hydrogen H, 0______Fluorine F, 10______Magnesium Mg, 12______

Europium Eu, 90______Mercury Hg, 121______

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

a. 26 electrons, 29 neutrons, 26 protons Iron, Fe______

b. 53 protons, 74 neutrons Iodine, I______

c. 2 electrons (neutral atoms) Helium, He______

d. 20 protons Calcium, Ca______

e. 0 neutrons Hydrogen, H______

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

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. Fill in the missing items in the table below.

Name / symbol / Z / A / #p / #e / #n / isotopic symbol
sodium / Na / 11 / 23 / 11 / 11 / 12 / 2311 Na
chlorine / Cl / 17 / 35 / 17 / 17 / 18 / 3517Cl
potassium / K / 19 / 39 / 19 / 19 / 20 / 3919 K
Name / symbol / Z / A / #p / #e / #n / isotopic symbol
phosphorus / P / 15 / 31 / 15 / 15 / 16 / 3115 P
iron / Fe / 26 / 56 / 26 / 26 / 30 / 5626 Fe
iodine / I / 53 / 127 / 53 / 53 / 74 / 12753 I
Name / symbol / Z / A / #p / #e / #n / isotopic symbol
silver / Ag / 47 / 108 / 47 / 47 / 61 / 10847 Ag
krypton / Kr / 36 / 84 / 36 / 36 / 48 / 8436 Kr
tungsten / W / 74 / 184 / 74 / 74 / 110 / 18474 W
  1. In a neutral atom, # Protons = # Electrons: True or False?
  2. Thallium 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 thallium-203 in nature c. Thallium-205 atoms have fewer neutrons

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

  1. Atoms consist of: (check all that apply) ProtonsNeutronsMoleculesElectrons
  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 ___6______protons.
  2. What do you call an atom that is positively or negatively charged because it gained or lost one or more electrons? Ion
  3. The valence electron(s) is/are theouter mostelectron(s) in an atom.
  4. The center of an atom is called the: nucleus
  5. In an atom, the electrons form a cloud around the nucleus.
  6. Objects that are electrically neutral becomenegatively charged when they gain electrons.
  7. In an element with a neutral charge, the atomic number is equal to the number of p+ & e‒.
  8. ______are particles with no charge. Protons NeutronsElectrons
  9. ______are negatively charged particles. ProtonsNeutronsElectrons
  10. ______are positively charged particles.ProtonsNeutronsElectrons
  11. The atom has the following parts

ions, protons, electrons protons, electrons, neutrons

protons, electrons, moleculeselements, neutron protons

  1. What charge do protons carry? PositiveNegative Neutral
  2. Is an atom the smallest particle of matter?True False
  3. Determine the average atomic mass of this mixture of naturally occurring isotopes of Barium.

Isotope / N.A.% / amu
Ba - / 130 / 0.106% / 0.1378
Ba - / 132 / 0.101% / 0.13332
Ba - / 134 / 2.417% / 3.23878
Ba - / 135 / 6.592% / 8.8992
Ba - / 136 / 7.854% / 10.68144
Ba - / 137 / 11.23% / 15.3851
Ba - / 138 / 71.7% / 98.946
Sum = / 137.4216
  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.