Download Unit 3 Chemical Foundations: Elements, Atoms, and Ions Section

Unit 3
Chemical Foundations: Elements, Atoms, and Ions
Section 3.1
The Elements
Key Term
Element symbols
Questions
1. Give four different chemical meanings for the word element and an example of each.
2. How many of the Top Ten elements in the human body are also Top Ten elements in the earth’s crust,
ocean, and atmosphere? What are these elements?
3. Make a list of the elements that you think were named after a place.
4. Give the symbol for each of the given elements.
a. Aluminum
b. Sodium
c. Mercury
d. Helium
e. Oxygen
f. Potassium
5. Give the name for each of the given symbols.
a. Ca
b. P
c. S
d. Si
e. Mg
f. C
6. The graph below shows the mass percentages of the five most abundant elements in the human
body. Use this graph to answer the following questions.
a. What is the fourth most abundant element by mass in the human body?
b. Which element is almost twice as abundant by mass as hydrogen in the human body?
c. What percentage of the human body is not made up of oxygen, carbon, or hydrogen?
Section 3.2
Atoms and Compounds
Key Terms
Law of constant composition
Dalton’s atomic theory
Atoms
Compound
Chemical formula
Questions
1. What observations led Dalton to propose his model for the atom?
2. What are the main ideas of Dalton’s atomic theory?
3. How was Dalton able to predict the formation of multiple compounds between the elements?
4. Did Dalton’s model of the atom include protons, neutrons, and electrons inside the atoms? Explain.
5. What information is given in a chemical formula?
6. Write the formula for each of the following substances, listing the elements in the order given.
a. A molecule containing two hydrogen atoms, one sulfur atom, and four oxygen atoms
b. List the hydrogen first.
c. A molecule containing one carbon atom and four hydrogen atoms
d. List the carbon first.
e. A molecule containing one sulfur atom and five fluorine atoms
f. (Carbon atoms)
Section 3.3
Atomic Structure
Key Terms
Electrons
Nuclear atoms
Nucleus
Proton
Neutron
Isotopes
Atomic number
Mass number
Questions
1. How is Thomson’s model of the atom different from Dalton’s model of the atom?
2. What caused Rutherford to propose a revised model of the atom? How is the Rutherford model
different from the previous models?
3. Copy and complete the following table.
Symbol
Number of
protons
Number of
neutrons
Number of
electrons
29
36
21
18
4. Write the symbol for each of the following. Determine the number of protons, neutrons, and
electrons in each atom.
a. A sodium atom with a mass of 24
b. A carbon atom with a mass of 13
c. A chlorine atom with a mass of 37
5. Write the symbol for each of the following.
a. The magnesium atom that has 12 neurons
b. The bromine atom that has 45 neutrons
c. The hydrogen atom that has 2 neutrons
6. Label the parts of the atom represented below and the charge of each part.
In addition, copy and complete the following table.
Atomic number of the atom
Name of the element
Symbol of the element
Mass number of the atom
Number of electrons in the atom
7. In two isotopes of the same element, which of the following would be the same and which would be
different?
-atomic number
-number of protons
-number of neutrons
-number of electrons
-element symbol
Section 3.4
Using the Periodic Table
Key Terms
Periodic table
Groups
Alkali Metals
Alkaline earth metals
Halogens
Noble gases
Transition metals
Metals
Nonmetals
Metalloids (semimetals)
Diatomic molecules
Questions
1. To what does the term periodic in periodic table refer?
2. Why are the elements in vertical groups on the periodic table called “families”?
3. What does the “stair-step” line on the periodic table tell you?
4. What does the term noble mean when referring to noble metals and noble gases?
5. Which elements exist naturally as diatomic molecules? Write their formulas.
6. Which elements are gases at 25 °C? Write their formulas.
7. Copy the table shown. Then use the periodic table to complete the table.
Family to which
Atomic
Metal or
Name
Symbol
the element
number
nonmetal?
belongs
Sodium
F
4
Calcium
47
8. Which two elements are liquids at 25 °C? Write their formulas.
Section 3.5
Ions and Their Compounds
Key Terms
Ion
Cation
Anion
Ionic compounds
Questions
1. Why does an atom have a net zero charge?
2. a. Show how fluorine forms an ion. Does it form a cation or an anion?
b. Show how lithium forms an ion. Does it form a cation or an anion?
3. What are the relationships between the group number on the periodic table and the types of ions
formed?
4. What evidence do we have that convinces us that sodium chloride is an ionic compound?
5. Give the formulas for the compounds that contain the following pairs of ions.
a. Al3+ and Clb. K+ and O2c. Ca2+ and S2d. Sr2+ and F-