Baird Chem in Your Life Chapter 03
Baird Chem in Your life Chapter 03
1. What particle of the atom distinguishes one element from another?
a. proton
b. electron
c. neutron
d. photon
a: Answer on page 75, the number of protons identifies the element and is called the atomic number.
2. What is the atomic number of oxygen?
a. 8
b. 4
c. 2
d. 16
a: Looking on the periodic table, the number above the symbol is the atomic number.
3. An electron has the following characteristics:
a. −1 charge, 0 amu
b. −1 charge, 1 amu
c. 0 charge, 1 amu
d. −1 charge, −1 amu
a: An electron has a negative charge and 0 amu mass.
4. Each atom of an element has almost all its mass in the ______.
a. nucleus
b. shells
c. protons
d. neutrons
a: The mass of an atom is from the mass of the protons and neutrons that are the particles in the nucleus.
5. Who was the scientist that performed the experiment with gold foil to show an uneven distribution of charge?
a. Rutherford
b. Bohr
c. Einstein
d. Dalton
a: Rutherford performed the experiment with gold foil explained on page 76.
6. The mass number of an element equals _____.
a. the number of protons plus neutrons
b. the number of neutrons
c. the number of protons
d. the number of protons plus electrons
a: Mass number is defined as the number of protons plus the number of neutrons.
7. The number of neutrons in a polonium atom that has a mass number of 210 is ______.
a. 126
b. 84
c. 168
d. 210
a: The atomic number of polonium is 84, and this number is subtracted from the mass number 210, which is 126.
8. Determine the mass number of a uranium atom that has 146 neutrons.
a. 238
b. 146
c. 235
d. 92
a: The atomic number of uranium is 92 and this number added to 146 neutrons equals 238 for the mass number.
9. What is the maximum number of electrons that can be contained in shell number 4?
a. 8
b. 16
c. 18
d. 32
a: The formula is 2N2, in which N equals the shell number. 42= 16 × 2 = 32 total electrons.
10. What would be the electron configuration for the calcium atom?
a. 2,8,8,2
b. 2,8,10
c. 2,8,6,4
d. 2,6,8,4
a: Two electrons maximum in the first shell, 8 electrons maximum in the second shell; the calcium atom has 4 shells and the last shell must have 2 electrons because it is in the second column; therefore, 2 + 8 + 2 = 12 subtracted from 20 total electrons equals 8 in the third shell.
11. What scientist was the first to construct a table of the elements based on repeating properties?
a. Mendeleev
b. Dalton
c. Rutherford
d. Bohr
a: Mendeleev was the first to construct a table of the elements, as described on page 86.
12. Which of the following does not belong to the group of elements called the halogens?
a. xenon
b. chlorine
c. iodine
d. astatine
a: Xenon is an inert gas and is not in the same group as Cl, I, and At.
13. How many valence electrons do elements that are in the group with nitrogen, phosphorus, and bismuth have?
a. five
b. three
c. four
d. six
a: The group number represents valence electrons. The group number of N, P, and Bi is 5 and therefore they have five valence electrons.
14. Using the Lewis structure, how many pairs of unshared electrons are in the H2O2 molecule?
a. four
b. two
c. six
d. eight
a: The Lewis structure arrangement of H O is HOOH, therefore, each oxygen atom has two pairs of unshared electrons, which equals four pairs.
15. How many bonds do elements of group V need in order to acquire an octet of electrons?
a. three
b. two
c. five
d. four
a: Because group 5 elements have five valence electrons, their atoms need three more electrons to equal eight electrons for the Octet Rule, which represents three bonds.