Chpt. 1 - Atomic Structure, Periodic Table, Electronic Structure

Question 1

An atom, the smallest unit of an element, is composed primarilly of three fundamental particles: electrons, protons, and neutrons. The combinations of these particles in an atom is distinct for each element. An atom of the element radon is composed primarily of a specific combination of what three basic particles?

Answer 1

electrons, protons, neutrons

Question 2

Each atom of the same element has the same combination of protons and electrons. An atom of the element helium in outer space has ____________ combination of electrons and protons as that of an atom of helium on earth.

Answer 2

the same

Question 3

Each element has a unique combination of protons and electrons in its atoms. The combination of electrons and protons in an atom of one element is different from that in an atom of any other element. Since each element has a known unique number of protons and electrons in its atoms, would it be possible to identify an element if you know the number of protons and electrons in its atoms?

Answer 3

yes (if you could compare the number of electrons and protons in your unknown atom with a list of the electrons and protons in atoms of each known element)

Question 4

Protons are particles with a positive (plus) charge. Electrons are particles with a negative (minus) charge. Unless otherwise stated, an atom is assumed to be neutral, with the positive and negative charges being equal. In any neutral atom, the num­ber of electrons (having a negative charge) is always equal to the number of protons (having a positive charge).

A boron atom contains five protons. We assume the atom to be neutral. How many electrons must it have?

Answer 4

five

Question 5

An atom contains eight electrons. How many protons does it contain?

Answer 5

eight

Question 6

Each element has a unique number of electrons and protons in its atoms. Since the number of electrons in a neutral atom is equal to the number of protons, do you think we can identify an element if we know just the number of protons in its atoms?

Answer 6

yes (if we could compare the number of protons in an atom of the unknown element with a list or table of the number of protons in atoms of every known element)

Question 7

The number of protons in an atom of an element is called its atomic number. What is the atomic number of the element helium (He)?

Answer 7

2

Question 8

The element zinc (Zn) has an atomic number of 30. How many protons does an atom of zinc contain?

Answer 8

30

Question 9

A neutral atom of zinc contains how many electrons?

Answer 9

30 (the same as the number of protons)

Question 10

Using the periodic table, determine the number of electrons in a neutral atom of copper (Cu).

Answer 10

29 (the same as the number of protons)

Question 11

What is the atomic number of the element represented?_________________ What element is represented? __________________

Answer 11

1 (The atomic number equals the number of protons.); hydrogen (H)

Question 12

An electron always carries a negative charge. A proton carries a charge exactly opposite that of the electron. A proton must therefore have a ________ charge.

Answer 12

positive

Question 13

An electron has very little mass when compared to a proton. It takes about 1836 electrons to equal the weight of just one proton. In a hydrogen atom consisting of just one proton and one electron, the greatest proportion by weight is accounted for by the ______________.

Answer 13

proton (The proton accounts for about 99.95% of the weight of a hydrogen atom and the electron 0.05%.)

Question 14

The element helium (He), represented by the Bohr model below, has an atomic number of _______.

Answer 14

2

Question 15

The neutral atom of He contains how many protons?_____ electrons? _____.

Answer 15

two; two

Question 16

The weight of an atom of helium is not totally accounted for by the protons and electrons. A third subatomic particle, the neutron, is responsible for the additional weight. The neutral atoms of all elements except the most common form of the element hydrogen have one or more neutrons in the nucleus of their atoms. The diagram below shows the neutrons in the corrected Bohr model of helium.

Since a neutral atom contains equal numbers of negatively charged electrons and positively charged protons, what type of electrical charge do you think is possessed by a neutron? _____________

Answer 16

no charge (The name neutron means a neutral particle.)

Question 17

A neutron is slightly heavier than a proton. Of the primary fundamental particles in an atom:

a. which is the lightest in weight?
b. which is the heaviest?
c. which is between the other two in weight?

Answer 17

(a) the electron; (b) the neutron; (c) the proto

Question 18

In the Bohr model of a lithium atom shown, which subatomic particle(s) is (are) represented by the circular orbits shown by the larger circles?___________

Which particle(s) make(s) up the nucleus or center of the atom? _________

Answer 18

electrons; protons and neutrons

Question 19

If the negative charge of an electron is represented by -1, the charge on the proton would be ______ and the charge on the neutron would be _______ .

Answer 19

+1; neutral

Question 20

The symbol “Ca” represents a neutral atom of the ele­ment calcium. Remembering the definition of a neutral atom, you know that “Ca” contains 20 protons and how many electrons?

Answer 20

20 (A neutral atom contains an equal number of protons and electrons.)

Question 21

The periodic table of the elements is made up of several rows and some columns.The rows are called periods and the columns are called groups. The groups are labeled IA, IIA, IIIB, and so on. The elements Be, Mg, Ca, Sr, Ba, and Ra are included in which group?

Answer 21

Group IIA

Question 22

The elements Li, Be, B, C, N, 0, F, and Ne are all members of a (group, period) __________ .

Answer 22

Period

Question 23

Groups are often called families because the elements that make up the groups or families have similar chemical properties. Argon (Ar) is part of Group VIIIA. It is a rather unreactive gas. Since families or groups of elements have similar properties, would you expect krypton (Kr) to be a highly reactive gas?_______

Answer 23

no (All of the elements in Group VIIIA are rather unreactive.)

Question 24

Because all Group VIIIA elements are rather unreactive and are gaseous at room temperature, they have been named the noble gas family. An element in Group VIIIA may be generalized by its family name as a(n) _________ gas.

Question 25

Group IA on the left side of the chart is often called by the family name of alkali metals (with the exception of hydrogen). These elements can react vigorously with water to form strong alkaline solutions. If a friend told you that aluminum (Al) was an alkali metal would he be right or wrong?

Answer 25

wrong (Aluminum is located in Group ILIA and the alkali metals are all located in Group IA.)

Question 26

Group IIA elements are known as the alkaline earth metals because the oxides of these metals (chemical compounds of the metals and oxygen) form alkaline solu­tions in water. The element potassium (K) can be classified as a(n) ________.

Answer 26

akali metal (Group IA)

Question 27

The element Ba (barium) can be classified as a(n) (alkali metal, alkaline earth, noble gas) ____________.

Question 28

An unknown element is placed in water. A vigorous reaction takes place, and the result is an alkaline solution. Of which family is the element probably a member? (alkaline earth, alkali metal, noble gas)_____________

Answer 28

alkali metal

Question 29

Metals have a lustrous or shiny surface and are solid at ordinary room temperature (with the exception of mercury, which is liquid at room temperature). Metal cooking utensils take advantage of what two properties of metal? (conducts electricity, conducts heat, ductile, solid)

Answer 29

Metal conducts heat and is solid

Question 30

Nonmetals are located on the right side of the steplike line in the periodic table. Which of the following families of elements are classified as nonmetals? (halogens, alkaline earths, noble gases) ____________________

Answer 30

halogens and noble gases

Question 31

Each shell (or floor) in the model has one or more apartments, which are called subshells. These subshells are apartments of four sizes: s, p, d, and f. An s subshell (apartment) has only a single room. A p subshell has three rooms. A d subshell has five rooms, while an f subshell has seven rooms. An s subshell then will hold a maximum of two electrons according to the model.

(a) A p subshell will hold a maximum of how many electrons?
(b) How many will a d subshell hold?
(c) How many will an f subshell hold?

Answer 31

(a) six (3 rooms x 2 electrons/room); (b) ten (5 rooms x 2 electrons/room); (c) fourteen (7 rooms x 2 electrons/room)

Question 32

Each room in a subshell is called an orbital. We know, then, that an s subshell will consist of one orbital with a capacity (occupancy) of two electrons.

(a) A p subshell will consist of three orbitals with a total subshell capacity of electrons.
(b) A d subshell will have orbitals and a total capacity of electrons.
(c) An f subshell will have ______ orbitals and hold _________ electrons.

Answer 32

(a) six (3 orbitals x 2 elect .ons per orbital); (b) five, ten; (c) seven, fourteen

Question 33

The first shell (floor) has only one subshell (apartment), which is an s subshell. Because of its location on the first shell, it is called a is subshell.

(a) How many orbitals (rooms) are there in this is subshell?
(b) How many electrons will the subshell hold?

Answer 33

(a) one (s subshells have only one orbital); (b) two (each orbital holds only two electrons)

Question 34

The second shell (floor) only has an s subshell (apartment) and a p subshell.

(a) If the s subshell is called 2s, what do you suppose the p subshell is called?
(b) How many orbitals (rooms) are in that p subshell?
(c) How many subshells are in the second shell?
(d) How many orbitals are there in the second shell?
(e) How many electrons can occupy the second shell?

Answer 34

(a) 2p; (b) three (p subshells have three orbitals); (c) two (s and p); (d) four (one s orbital and three p orbitals); (e) eight (4 orbitals x 2 electrons/orbital)

Question 35

The third shell has three subshells: s, p, and d.

(a) What are they called?
(b) How many subshells are in the third shell?
(c) How many orbitals are in the third shell?
(d) How many electrons can be in the third shell?

Answer 35

(a) 3s, 3p, 3d; (b) three; (c) nine (ones orbital, three p orbitals, and five d orbitals; (d) 18(9 orbitals x 2 electrons/orbital)

Question 36

Shells 4 through 7 each have four subshells: s, p, d, and f.

(a) What would you call the subshells on the fourth shell?
(b) Sixth shell?

Answer 36

(a) 4s, 4p, 4d, 4t; (b) 6s, 6p, 6d, 6f

Question 37

Let’s review what we have just learned. Assume that we have only seven floors in our “building.”

(a) A shell may have as many as _______ subshells or as few as ______ subshell(s).
(b) A subshell may have as many as ______ orbitals or as few as ________ orbital(s).
(c) A subshell may hold as many as ______ electrons or as few as ________ electron(s), assuming full occupancy.
(d) A shell may hold as many as ______ electrons or as few as _________ electrons, assuming full occupancy.

Answer 37

(a) four, one; (b) seven, one; (c) 14, two; (d) 32, two

Question 38

As we have mentioned previously, electrons prefer the lower shells (floors) and the smaller subshells (apartments). Electrons prefer the smaller subshells to such a degree that they will sometimes occupy a smaller subshell on the next higher shell rather than the larger subshell on the lower shell.

By experimentation, it has been determined that electrons will fill the 1s sub-shell (apartment) first. They will then fill the 2s subshell, and then the 2p subshell. Next, they will fill the 3s subshell and then the 3p subshell. However, before going into the large five orbital 3d subshell, electrons will first fill the 4s subshell. After filling the 4s subshell, electrons will then proceed to fill the 3d subshell. The 4p subshell is filled next. The electrons prefer to fill the small 5s subshell before filling the larger 4d subshell. The 4d is filled after 5s. Next, the electrons fill the 5p subshell. Then the small 6s subshell is filled. The very large 4f subshell is occupied only after 6s is filled. After 4f comes 5d. Next is 6p, then 7s, and then 5f.

Note: that as we fill consecutive subshells, the energy of the electrons increases. Electrons in the 2s subshell have a higher energy than electrons in the is subshell; 2p electrons have a higher energy than 2s electrons, and so on.

Using the diagram, which subshell is filled first?

Answer 38

1s

Question 39

Note the unpaired or single electrons in the partially filled 2p subshell. The electrons occupy as many orbitals as possible in the same subshell before pairing with another electron. This is known as the Principle of Maximum Multiplicity. Using the Principle of Maximum Multiplicity and the arrow notation, indicate the arrangement of electrons for the following.

(a) ₁₄Si ______________
(b) ₁₆S _______________
(c) ₂₃S _______________
(d) ₂₆Fe _______________

Answer 39

(a) ₁₄Si
(b) ₁₆S
(c) ₂₃S
(d) ₂₆Fe

Question 40

The electron configurations of the noble gases are given below.

₂He 1s²

₁₀Ne 1s² 2s² 2p⁶

₁₈Ar 1s² 2s² 2p⁶ 3s² 3p⁶

₃₆Kr 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶

₅₄Xe 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶

₈₆Rn 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d¹⁰ 6p⁶

With the exception of 2He, the subshell of greatest energy (last subshell) in each noble gas consists of six electrons occupying a(n) (s, p, d, f) subshell. ____

Answer 40

p