ASTR 113 Chapter 5
An atom of the element iron has an atomic number of 26 and an atomic weight of 56. If it is neutral, how many protons, neutrons, and electrons does it have?
26 protons, 30 neutrons, 26 electrons
An atom which has 4 protons and 6 neutrons will be electrically neutral if it contains
4 electrons
The most common isotope of gold has atomic number 79 and atomic weight 197. How many protons does its nucleus contain? How many neutrons does its nucleus contain? How many electrons are there in a neutral atom of gold? If the gold is triply ionized, how many electrons does it have?
79, 118, 79, 76
The most common isotope of oxygen has atomic number 8 and atomic mass number 16. How many protons does its nucleus contain? How many neutrons does its nucleus contain? How many electrons are there in a neutral atom of oxygen? Another isotope of oxygen has two extra neutrons. What is the atomic number of this isotope? What is the atomic mass number of this isotope?
8, 8, 8, 8, 18
An isotope of fluorine has 9 protons and 10 neutrons. What is its atomic number? What is its atomic mass number? How many electrons are there in a neutral atom of fluorine? If we added a proton to this fluorine nucleus, would the result still be fluorine? If instead we added a neutron to this fluorine nucleus, would the result still be fluorine?
9, 19, 9, no, yes
The most common isotope of uranium is U-238, but the form used in nuclear bombs and nuclear power plants is U-235. Given that uranium has atomic number 92 How many protons does the nucleus of U-238 contain? How many neutrons does the nucleus of U-238 contain? How many protons does the nucleus of U-235 contain? How many neutrons does the nucleus of U-235 contain?
92, 146, 92, 143
Which of the following statements about electrical charge is true?
A positive charge and a negative charge will attract eachother
Each of the following describes an "Atom 1" and an "Atom 2." In which case are the two atoms different isotopes of the same element?
Atom 1: nucleus with 7 protons and 8 neutrons, surrounded by 7 electrons; Atom 2: nucleus with 7 protons and 7 neutrons, surrounded by 7 electrons.
Each of the following describes an "Atom 1" and an "Atom 2." In which case are the two atoms isotopes of each other?
Atom 1: nucleus with 92 protons and 143 neutrons, surrounded by 92 electrons Atom 2: nucleus with 92 protons and 146 neutrons, surrounded by 92 electrons
Consider an atom of oxygen in which the nucleus contains 8 protons and 8 neutrons. If it is doubly ionized, what is the charge of the oxygen ion and how many electrons remain in the ion?
Charge = +2; number of remaining electrons = 6.
Consider an atom of gold in which the nucleus contains 79 protons and 118 neutrons. What is its atomic number and atomic weight?
The atomic number is 79, and the atomic weight is 197.
Consider an atom of gold in which the nucleus contains 79 protons and 118 neutrons. If it is doubly ionized, what is the charge of the gold ion and how many electrons remain in the ion?
The gold ion has a charge of +2 and 77 electrons
Which of the following best describes the fundamental difference between two different chemical elements (such as oxygen and carbon)?
They have different number of protons in their nucleus
Suppose you built a scale-model atom in which the nucleus was the size of a pinhead. About how big would the entire atom be?
a about a hundred meters
What is a compound?
a molecule containing two or more elements
How much electrical charge does an atom with 6 protons, 6 neutrons, and 5 electrons have?
a positive charge of +1
Consider an atom of carbon in which the nucleus contains 6 protons and 7 neutrons. What is its atomic number and atomic mass number?
atomic number = 6; atomic mass number = 13
An atom that has fewer electrons than protons is called a/an
ion
When an atom loses an electron, it becomes
ionized
The loss of an electron from a neutral helium atom results in
ionized helium
