Chemical Interactions Ch. 1 Study Guide ANSWER KEY

  1. Draw a picture of an atom including the protons, neutrons, and electrons.

Protons and neutrons should be inside the nucleus.

Electrons are outside the nucleus in the electron cloud.

  1. What type of charge does each of the following have?
  1. Protons Positive (+1)
  1. Neutrons No Charge
  1. Electrons Negative (-1)
  1. What are isotopes? What makes an isotope different from a regular element? (at least 3 sentences)

Isotopes are elements that have a different number of neutrons than normal

Isotopes also have a different atomic mass than normal.

Isotopes are named by their atomic mass (ex. C-14, carbon with an atomic mass of 14)

  1. Atoms of an element always have a certain number of protons.
  1. Fill in the chart

Element Symbol / Protons / Neutrons / Electrons / Group # / Period # / Type (metal, non-metal, or metalloid)
Na / 11 / 12 / 11 / 1 / 3 / Metal
P / 15 / 16 / 15 / 5 / 3 / Non-metal
Ne / 10 / 10 / 10 / 8 / 2 / Non-metal
Si / 14 / 14 / 14 / 4 / 3 / Metalloid
Br / 35 / 45 / 35 / 7 / 4 / Non-metal
Ca / 20 / 20 / 20 / 2 / 4 / metal
  1. What does the atomic number of an element tell you? The number of protons
  1. If an atom loses electrons then is becomes a postitive ion. If an atom gains electrons then is becomes a negative ion.
  1. # protons + # neutrons = atomic mass
  1. Non-metals are elements that usually bond with metals to form salt. They are also often used to kill bacteria.
  1. List some characteristics of each of the following (you may need to use your book)
  1. metals –elements that conduct electricity, heat well, and have a shiny appearance
  1. reactive metals –very reactive metals
  1. transition metals –less reactive than other metals. 2 or more metals are combined to form an alloy
  1. noble gases –almost never react with other elements
  1. halogens –often “forms salts” with metals. Very reactive non-metals
  1. metalloids –have properties of both metals and non-metals
  1. What does the group number on the periodic table tell you? The number of valance electrons or the number of electrons in the outer shell.
  1. What does the period number on the periodic table tell you? The number of shells or energy levels
  1. What group number do the most reactive elements belong to? Group 1
  2. Fill in the chart for the isotopes and ions.

Element Symbol / Protons / Neutrons / Electrons
Ne – 23 / 10 / 13 / 10
Mg – 21 / 12 / 9 / 12
Br+3 / 35 / 45 / 32
F-1 / 9 / 10 / 10
  1. List the number of valance electrons for each of the following elements and name the ion that will make it “happy and full”.

Element Symbol / Valance Electrons / Ion to make it “happy and full”
Oxygen – O / 6 / O-2
Magnesium – Mg / 2 / Mg+2
Lithium - Li / 1 / Li+1
  1. Draw the following elements on a separate sheet of paper: Silicon, Nitrogen, Helium, and Sodium

Silicon – (14 protons 14 neutrons in middle) 3 shells – 4 electrons in outer shell

Nitrogen – (7 protons 7 neutrons in middle) 2 shells – 5 electrons in outer shell

Helium – (2 protons 2 neutrons in middle) 1 shell – 2 electrons in outer shell

Sodium – (11 protons 12 neutrons in middle) 3 shells – 1 electron in outer shell