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Basic Definitions
The Atom
The Periodic Table
Electron Dot Diagrams
pH
100
The smallest possible unit of a chemical element
What is an atom?
100
What are the three subatomic particles?
Protons, neutrons, and electrons
100
There are ___ naturally occurring elements.
What is 92?
100
Use a PT to draw the electron dot diagram for hydrogen. Be sure to show protons, neutrons, and electrons in their proper orientations.
Nucleus: 1 proton, 0 neutrons. First energy level (EL) 1 electron.
100
A substance such as lemon juice, with a pH of 2, is a(n):
What is an acid?
200
The smallest possible unit of a chemical compound.
What is a molecule?
200
In terms of charge, protons are __, neutrons are __, and electrons are __.
protons are positive, neutrons are neutral, and electrons are negative
200
In the periodic table, elements are arranged according to ___.
What is atomic number, or the number of protons in the atom?
200
Use a PT to draw the electron dot diagram for carbon. Be sure to show protons, neutrons, and electrons in their proper orientations.
Nucleus: 6 protons, 6 neutrons. EL1-2 electrons, EL2-4 electrons.
200
Baking soda has a pH of 8, while bleach has a pH of 12. Which is the stronger base?
Bases increase in strength as you approach 14. Therefore, bleach is a stronger base.
300
A pure substance composed of two or more elements
What is a compound?
300
In terms of mass, protons have a mass of __, neutrons have a mass of __, and electrons have a mass of __.
Protons have a mass of 1 amu (atomic mass unit), neutrons have a mass of 1 amu, and electrons have a mass of almost 0 amu.
300
Determine the number of protons for the following entry: Magnesium: Atomic Number 12, Atomic Weight 24.
The number of protons and the atomic number are equivalent. Therefore, the answer is 12.
300
Use a PT to draw the electron dot diagram for flourine. Be sure to show protons, neutrons, and electrons in their proper orientations. Then predict whether it will be chemically reactive or nonreactive.
Nucleus: 9 p, 10 n. EL1-2electrons; EL2 7 electrons. F is chemically reactive because it has an unfilled outer energy level.
300
If a substance releases H+ in solution, it is considered a(n):
What is an acid?
400
A pure substance composed of only one type of atom.
What is an element?
400
Since they orbit the nucleus, ___ are primarily involved in determining the chemical behavior of the atom.
What are electrons?
400
Determine the protons and neutrons for the following element: Phosphorus, Atomic Number 15, Atomic Weight 31.
Since the AN is 15, there are 15 protons. Neutrons are calculated by subtracting AN from AW, so the answer is 31-15=16 neutrons.
400
Use a PT to draw the electron dot diagram for sodium. Be sure to show protons, neutrons, and electrons in their proper orientations. Then predict whether it will be chemically reactive or nonreactive. Finally, predict whether it will be likely to gain or lose electrons.
Nucleus: 11 p, 12 n. EL1-2 electrons; EL2-8 electrons; EL3-1 electron. Chemically reactive because unfilled outer EL. Likely to lose one electron to become stable.
400
Consider the following formula: HCl + NaOH --> NaCl + H20 Identify at least one acid, one base, and one neutral compound.
HCl is an acid (releases H+ in solution), NaOH is a base (releases OH- in solution). NaCl is a salt (always formed by the combination of an acid and a base), and H2O is the prototypical neutral compound.
500
Complete the following analogy (comparison): Slice is to pizza as atom is to _______.
AWV, but will most likely include molecule (or compound).
500
Radioactive substance emit particles from their nucleus over time. Based on your knowledge of the atom, which two particles would you therefore expect a radioactive element to emit?
Since they are being emitted from the nucleus, the proton and neutron are the most likely candidates. In truth, this is not quite right, but for now, it serves as a rough approximation of nuclear decay.
500
Use a Periodic Table to solve the following. An element has 79 electrons. Identify the element, provide the Atomic Weight, and the number of protons, neutrons, and electrons.
If the element has 79 electrons, it also has 79 protons. Therefore, the element is Au, Gold. The AW is 197. The neutrons are 197-79=118.
500
Use a PT to draw the electron dot diagram for chlorine. Be sure to show protons, neutrons, and electrons in their proper orientations. Then predict whether it will be chemically reactive or nonreactive. Finally, predict whether it will be likely to gain or lose electrons.
Nucleus: 17 p, 18 n. EL1-2 electrons; EL2-8 electrons; EL3-7 electrons. Chemically reactive because unfilled outer EL. Likely to gain one electron to become stable.
500
Lemon juice has a pH of 2, while milk has a pH of 5.5. Predict the concentration of H+ as it relates to lemon juice and milk.
The strength of an acid increases as the pH scale approaches 0. Therefore, lemon juice must be a stronger acid than milk. The concentration of H+ increases as the strength of an acid increases. Therefore, lemon juice must have more H+ than milk.