Chapter 4 Online HW

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

On a mission to a newly discovered planet, an astronaut finds gallium abundances of 61.29% for 69-Ga and 39.71% for 71-Ga. What is the atomic mass of gallium for this location? The mass of 69-Ga is 68.7200amu . The mass of 71-Ga is 70.9200amu . Express your answer to two decimal places, and include the appropriate units.

70.28 amu

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

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

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

Locate 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

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.

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

Which of the following statements about protons are false? Check all that apply. A) Protons have the magnitude of charge as neutrons, but are opposite in sign. B) Some atoms do not have any protons. C) Protons have about the same mass as neutrons. D) Protons have about the same mass as electrons.

A) Protons have the magnitude of charge as neutrons, but are opposite in sign. B) Some atoms do not have any protons. D) Protons have about the same mass as electrons.

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

What does the atomic number of an element specify? A) The atomic number of an element is equal to the total number of subatomic particles containing the atom of this element. B) The atomic number of an element is equal to the number of protons found within the atomic nucleus. C) The atomic number of an element is equal to the number of neutrons found within the atomic nucleus. D) The atomic number of an element is equal to the total number of protons and neutrons found within the atomic nucleus.

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

What is a chemical symbol? A) A chemical symbol is a one or more letter abbreviation that is unique to each chemical compound. B) A chemical symbol is an unique type of atoms. C) A chemical symbol is a one or two letter abbreviation that is unique to each element. D) A chemical symbol is the special non-alphabetic symbol used for abbreviation of chemical compounds, for example middle dot or square brackets.

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

What are three main ideas in Dalton's atomic theory? Check all that apply. A) Most of the atom's mass and all of its positive charge are contained in a small core called the nucleus. B) There are as many negatively charged electrons outside the nucleus as there are positively charged particles (protons) inside the nucleus, so that the atom is electrically neutral. C) Atoms combine to form compounds in simple, whole number ratios. D) All atoms of an element are identical, and each element has unique atoms. E) Elements are composed of atoms. F) Most of the volume of the atom is empty space through which the tiny, negatively charged electrons are dispersed.

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