04 Chapter HW

Determine the charge of each of the following ions.

1. tungsten ion with 68 electrons = 6+ 2. tellurium ion with 54 electrons =2- 3. nitrogen ion with 10 electrons = 3- 4. barium ion with 54 electrons = 2+

What is the mass number of an ion with 105 electrons, 159 neutrons, and a +1 charge?

A = mass number = Number of protons in nucleus + Number of neutrons in nucleus Number of protons = Number of electrons + 1 ( since the charge is +1 due to lacking one electron ) Number of protons = 105 + 1 = 106 protons A = 106 protons + 159 neutrons = 265

Write isotopic symbols of the form X-A (for example, C−13) for each of the following isotopes. A) the iodine isotope with 74 neutrons B) the phosphorus isotope with 16 neutrons C) the uranium isotope with 234 neutrons D) the argon isotope with 22 neutrons

A) I-127 B) P-31 C) U-326 D) Ar-40

Predict how many electrons will most likely be gained or lost by each of the following. A) I B) Ba C) Cs D) Se

A) gain 1 electron B) lose 2 electrons C) lose 1 electron D) gain 2 electrons

Which of the following elements do you expect to be most like sulfur?

Oxygen

What are three main ideas in Dalton's atomic theory?

-Elements are composed of atoms -Atoms combine to form compounds in simple, whole number ratios -All atoms of an element are identical, and each element has unique atoms

Which statements are inconsistent with Dalton's atomic theory as it was originally stated?

-Two oxygen atoms combine with a carbon atom to form carbon dioxide molecules (T) -An oxygen atom combines with 1.5 hydrogen atoms to form water molecules (F) -Helium atoms can be split into two hydrogen atoms (F) -All carbon atoms are identical. (T)

The astronaut then measures the abundance of magnesium on the new planet, obtaining the following results: Isotope Abundance (%) Mass (amu) 24Mg 78.99 23.99 25Mg 10.00 24.99 26Mg 11.01 25.98 What is the atomic mass of magnesium for this planet? Express your answer to two decimal places, and include the appropriate units.

24.31 amu

Silicon has three naturally occurring isotopes: Si−28 with mass 27.9769 amu and a natural abundance of 92.21%, Si−29 with mass 28.9765 amu and a natural abundance of 4.69%, and Si−30 with mass 29.9737 amu and a natural abundance of 3.10%. Calculate the atomic mass of silicon. Express your answer using four significant figures.

28.09 amu

If the natural abundance of Br−79 is 50.69 %, what is the natural abundance of Br−81?

49.31%

On a mission to a newly discovered planet, an astronaut finds copper abundances of 69.97 % for 63Cu and 31.03 % for 65Cu. What is the atomic mass of copper for this location? The mass of 63Cu is 62.9300 amu . The mass of 65Cu is 64.9200 amu .

64.18 amu

If the mass of Br−81 is 80.9163 amu, what is the mass of Br−79?

78.919 amu

What is a chemical symbol?

A chemical symbol is a one or two letter abbreviation that is unique to each element.

Silver has two naturally occurring isotopes (Ag−107 and Ag−109). A) Use the periodic table to find the atomic mass of silver. Express your answer using five significant figures. B) If the natural abundance of Ag−107 is 51.84 %, what is the natural abundance of Ag−109? Express your answer using four significant figures. C) If the mass of Ag−107 is 106.905 amu, what is the mass of Ag−109? Express your answer using four significant figures.

A) 107.87 amu B) 48.16% C) 108.9 amu

ocate each of the following on the periodic table and give their group number. A) alkali metals B) alkaline earth metals C) halogens D) noble gasses

A) 1A B) 2A C) 7A D) 8A

Determine the charge of each ion. A) Oxygen ion with 10 electrons B) Aluminum ion with 10 electrons C) Titanium ion with 18 electrons D) Iodine ion with 54 electrons

A) 2- B) 3+ C) 4+ D) 1-

Which of the following statements about electrons are true? Check all that apply. A) Electrons are attracted to protons. B) Electrons repel each other. C) Electrons are much lighter than neutrons. D) Some electrons have a charge of 1- and some have no charge.

A) Electrons are attracted to protons. B) Electrons repel each other. C) Electrons are much lighter than neutrons.

Classify each of the following elements as a metal, nonmetal, or metalloid. A) Na B) Ge C) Si D) Br E) Ag

A) metal B) metalloid C) metalloid D) nonmetal E) metal

Copper has two naturally occurring isotopes. Cu−63 has a mass of 62.939 amu and relative abundance of 69.17%. Use the atomic weight of copper to determine the mass of the other copper isotope.

AMU = 64.92

Which of the following statements are inconsistent with Rutherford's nuclear theory as it was originally stated? Check all that apply. A) Helium atoms have two protons in the nucleus and two electrons outside the nucleus. B) Aluminum atoms have 13 protons in the nucleus and 22 electrons outside the nucleus. C) The majority of the mass of nitrogen atoms is due to their 7 electrons. D) Most of the volume of hydrogen atoms is due to the nucleus.

B) Aluminum atoms have 13 protons in the nucleus and 22 electrons outside the nucleus. C) The majority of the mass of nitrogen atoms is due to their 7 electrons. D) Most of the volume of hydrogen atoms is due to the nucleus.

Which of the following pairs of elements do you expect to be most similar? A) Na and Mg B) Cl and F C) N and Ni D) Mo and Sn E) Si and P

B) Cl and F

Which of the following elements are main-group elements?

Te K

What does the atomic number of an element specify?

The atomic number of an element is equal to the number of protons found within the atomic nucleus.

Match each property to the appropriate subatomic particle.

The proton Symbol p, neutron, and electron are the three main subatomic particles that make up all the elements.

Sort the subatomic particles according to their masses

The proton and neutron both have masses of about 1 amu, whereas the electron mass is only about 5.5×10−4amu.

III. Determine the number of protons and electrons in each of the following. p e

a) Al 3+ = 13, 10 b) S 2- = 16 , 18 c) I- = 53, 54 d) Ag+ = 47, 46

Which statement best summarizes the nuclear model of the atoms that emerged from Rutherford's gold foil experiment? a. The atom is composed of a dense core that contains most of its mass and all of its positive charge, while low-mass negatively charged particles compose most of its volume. b. The atom is composed of a sphere of positive charge with many negatively charged particles within the sphere. c. Most of the mass of the atom is evenly distributed throughout its volume. d. All of the particles that compose an atom have exactly the same mass.

a. The atom is composed of a dense core that contains most of its mass and all of its positive charge, while low-mass negatively charged particles compose most of its volume.