CHE 100 - Ch. 4
Match the following chemical symbols to their correct names.
1 = Aluminum (Al) 2 = Ar (Argon) 3 = Gold (Au) Using the periodic table you can find the chemical symbols as well as the names for all of the elements.
What is the precise mass of the proton?
1.00727 amu The mass of the proton is slightly more than 1 amu, but not quite the mass of the neutron. The atomic mass unit is defined to be roughly the same as one proton or neutron, but precise masses of individual atoms cannot be calculated by summing the individual protons and neutrons. Instead 1 amu is defined to be exactly 1/12 the mass of a carbon-12 atom, and the masses of individual protons and neutrons are slightly larger than 1 amu. The proton has a mass of 1.00727 amu.
How many electrons does O2−O2− contain?
10 electrons The following equation can be used to determine the number of electrons in an element. overall charge=number of protons−number of electrons overall charge=number of protons−number of electrons The overall charge of the ion is −2−2. Rearranging and using the atomic number for the number of protons, we can solve for the number of electrons: number of electrons=number of protons−overall charge number of electrons=number of protons−overall charge number of electrons=8−(−2)=10
What is the atomic mass of xenon?
131.294 Xenon has an atomic mass of 131.294 amu and an atomic number of 5454.
Which group on the periodic table contains the noble gases?
18 Group 1 - alkali metals Group 2 - alkaline earth metals Groups 3-12 - transition metals Group 15 - pnictogens Group 16 - chalcogens Group 17 - halogens Group 18 - noble gases
How many groups are on the periodic table?
18 The 18 groups are represented by the 18 columns on the table. Groups are labeled at the top of each column. In the United States, the labels were traditionally Roman numerals with capital letters. All columns, apart from the transition metals, are numbers from IA to VIIA. The transition metals (in the middle of the periodic table) are numbered from IB to VIIIB. However, IUPAC recommends that the numbers 1 through 18 be used, and these labels are more common.
Copper occurs naturally as 63Cu and 65Cu. Given that copper's atomic mass is 63.54, determine which isotope is more abundant.
63Cu Because the average atomic mass of copper is closer to 63 than it is to 65, we can conclude that 63Cu is the more abundant isotope.
Write the correct atomic symbol (including the atomic number) for an isotope with 54 protons and 78 neutrons. Write the answer in the form XZA using the atomic symbol button in the toolbar, where A is the mass number, Z is the atomic number, and X is the chemical symbol for the unknown element. Be sure to use the periodic table to identify the correct atomic symbol, which should be used in the answer.
An isotope with 54 protons and 78 neutrons has an atomic number of 5454 and a mass number of 54+78=132. Look up the atomic number on the periodic table to find the elemental symbol, Xe. The atomic symbol is written with the atomic number on the lower left and the mass number on the upper left, so it is 132 54/Xe
Write the atomic symbol (including the atomic number) for an isotope with 64 protons and 96 neutrons. Write the answer in the form XZA using the atomic symbol button in the toolbar, where A is the mass number, Z is the atomic number, and X is the chemical symbol for the unknown element.
An isotope with 64 protons and 96 neutrons has an atomic number of 64 and a mass number of 64+96=160. Look up the atomic number on the periodic table to find the elemental symbol, Gd. The atomic symbol is written with the atomic number on the lower left and the mass number on the upper left, so it is 160 64/Gd
An ion found in some compounds used as antiperspirants contains 1313 protons and 1010 electrons. What is its symbol?
Because the number of protons remains unchanged when an atom forms an ion, the atomic number of the element must be 13. We, thus, use the periodic table to identify the element as Al (aluminum). The Al atom has lost three electrons and, thus, has three more protons (13) than electrons (10). This is the aluminum cation, Al3+
Look at the periodic table Considering Chlorine has two main isotopes: Chlorine-35 and Chlorine-37, which of the two do you anticipate to be in more abundance? (in other words, which is there more of in the world?)
Chlorine-35 is more abundant because chlorine's atomic mass is closer to 35 than 37.
Why don't we add the number of electrons to get mass number?
Electrons weigh very little compared to protons and neutrons so their mass is negligible.
Which element has an atomic mass of approximately 59 amu?
Ni Nickel has an atomic mass of 58.693 amu58.693 amu. This is the closest atomic mass to 59 amu59 amu of the answer choices.
Which of the following are valid chemical symbols? Select all that apply.
O He F O (oxygen), He (helium), and F (fluorine) are all valid chemical symbols. Ua is not a valid chemical symbol, as no corresponding element exists.
Which of the tables below correctly pairs subatomic particles with their corresponding charges?
Particle Charge proton positive electron negative neutron neutral Protons have a positive charge and are located in the center of the atom with neutrons which have a neutral charge. Electrons orbit around the positive center and have a negative charge.
What is the atomic number of the element above?
The atomic number of the element shown in the problem is 74. The atomic number appears above the element symbol on an element block. We use the periodic table to arrange the elements and identify specific properties. While all periodic tables provide us with information about the elements, they do not always look identical. Element blocks will usually contain the atomic number, symbol, name, and atomic mass of each element. The figure below provides you with a quick reminder on how to read an element block:
Which is NOT a property of the alkaline earth metals?
They are gases. The alkaline earth metals, in group 22 are solid metals.
Which of the following is a correct statement about different elements that are in the same group in the periodic table?
They are in the same column of the periodic table. The vertical columns in the periodic table are called groups. Elements in the same column or group of the periodic table often have similar chemical properties.
Write the atomic symbol (including the atomic number) for the isotope of neodymium with 90 neutrons. Write the answer in the form XZA using the atomic symbol button in the toolbar, where A is the mass number, Z is the atomic number, and X is the chemical symbol for the unknown element.
Using the periodic table to find "neodymium," the symbol is Nd and the atomic number is 60, which is also the number of protons. An isotope with 60 protons and 90 neutrons has mass number of 60+90=150. The atomic symbol is written with the atomic number on the lower left and the mass number on the upper left, so it is 150 60/Nd
Write the atomic symbol (including the atomic number) for phosphorus-32. Write the answer in the form ZA using the atomic symbol button in the toolbar, where A is the mass number, Z is the atomic number, and X is the chemical symbol for the unknown element.
Using the periodic table to find phosphorus, the symbol is PP and the atomic number is 1515, which is also the number of protons. The number 3232 in the name of the isotope is the mass number. The atomic symbol is written with the atomic number on the lower left and the mass number on the upper left, so it is 32 15/P
The reason that atomic numbers are always integer values is because every element has:
a particular number of protons The atomic number refers to the number of protons in an atom, which is always a specific number for a given element.
The symbol Fe could refer to which of the following? Select the best answer below.
all of the above: an iron atom, the element known as "iron", a macroscopic sample of iron Fe means "iron" and it can be used to represent an individual iron atom in a molecular formula, or a ratio of iron atoms to other elements or compounds in a reaction, or just to represent the element itself without reference to any specific sample of iron.
Which has the smallest mass?
an electron Electrons have much less mass than protons and neutrons, and all of these are much smaller than an atom.
A term we use to represent the *average* mass of all atoms of an element is _______________.
atomic mass
Which number(s) is/are found on the periodic table? Read all choices and choose the best answer.
atomic number and atomic mass
Which of the following gives all of the information necessary to determine the number of subatomic particles?
atomic symbol The atomic symbol includes the elemental symbol, the atomic number and the mass number. The latter two are the number of protons and the sum of the number of protons and neutrons, so it is possible to find the number of neutrons by subtracting atomic number from mass number.
The number underneath the element on the period table is the _______________ for that element.
average atomic mass
Reminder: Which term(s) is/are synonymous with atomic mass? Choose the best answer.
average atomic mass and atomic weight can both be used to mean atomic mass but mass number cannot be used to represent the same thing as atomic mass
Rank the following polyatomic ions from fewest to most oxygen atoms: 1. Chlorate 2. Chlorite 3. Perchlorate
chlorite, chlorate, perchlorate The correct order from fewest to most oxygen atoms for these polyatomic ions is as follows: chlorite, chlorate, and perchlorate. Recall that -ate and -ite are the suffixes used to designate polyatomic ions containing more and fewer oxygen atoms, respectively. Per- (short for "hyper") and hypo- (meaning "under") are prefixes signifying even more oxygen atoms than -ate and even fewer oxygen atoms than -ite, respectively. Therefore, ClO−2 is the formula for chlorite, ClO−3 is the formula for chlorate and ClO−4 is the formula for perchlorate.
The charges on the proton and electron are typically measured in:
coulombs These fundamental particles bear the fundamental unit of charge, which is either positive or negative 1.602×10−191.602×10−19 coulombs.
Which element weighs, on average, approximately one atomic mass unit?
hydrogen Hydrogen, typically containing just one proton and one electron, will have an average mass of approximately one atomic mass unit.
The noble gases are also called the:
inert gases Nobel gases are also known as inert gases because they are for the most part completely unreactive.
Boron-10 and Boron-11 are ______________ of each other because they have the same number of ________________ but different number of _________________. (Answers are listed in the same order as the answer blanks).
isotopes; protons; neutrons
The chemical symbol "CL" with two capital letters is used to represent which element?
it is not a valid chemical symbol CL is not a valid chemical symbol because chemical symbols that contain 22 letters must have one upper case letter and one lower case letter, not 22 upper case letters.
So what is the term for the number of protons + the number of neutrons in an atom?
mass number
So which number can be the mass of a single atom?
mass number only
Atoms of the same element can differ in which of the following?
mass numbers Atoms of a specific element have a particular atomic number (which is the same as the number of protons), but may have different mass numbers, which correspond to different numbers of neutrons.
Atoms of the same element can have different:
mass numbers By definition, atoms of a given element have a particular atomic number (which is the same as the number of protons), but they can have different mass numbers if they have differing numbers of neutrons.
Elements in group 2 are:
metals All elements in group 22 are metals. Metals are elements that are shiny, malleable, good conductors of heat and electricity.
The group that is least likely to ionize is the __________.
noble gases The noble gases are also called the inert gases because they are very unlikely to react. This is because they have a full valence shell of electrons, which means they do not want to gain or lose any electrons. The other groups listed all readily ionize.
The mass number of an atom is equal to:
number of protons + number of neutrons The mass number of an atom is equal to the number of protons plus the number of neutrons found in the nucleus, each of which as an atomic mass of 1. For example, a typical carbon nucleus contains 6 protons and 6 neutrons and has a mass number of 12.
What is the general name for polyatomic ions that contain one or more oxygen atoms?
oxyanions Oxyanions are particularly common among polyatomic ions. Oxyanions are polyatomic ions that contain one or more oxygen atoms. Two specific oxyanions are peroxide, O/2/−2, and hydroxide, OH−.
The number of ________________ determines the identity of an element.
protons
What is another word for period?
series A period is also referred to as a series. The period, or series, groups elements based on their atomic orbitals.
Elements in the same group display __________ behavior.
similar Elements in the same group on the periodic table display similar behavior. For example, sodium (Na) and potassium (K) are both in group 11, so they will display similar behavior when interacting with other elements.
The prefix in subatomic tells us that subatomic particles are:
the basic building blocks of atoms The prefix "sub" can mean below, under, or imply that something is more basic than something else. All of these contexts can apply here, to state that subatomic particles are less massive than atoms, take up less space than atoms, or more generally that they comprise atoms.
We add the number of protons and neutrons to get what?
the mass number