Question 1

Which of the following elements is present in the fourth period of Group 3A?

Accepted Answer

Group 3A is also known as Group 13 and includes the elements boron (B), aluminum (Al), gallium (Ga), indium (In), and thallium (Tl). The fourth period on the periodic table corresponds to the row containing elements with atomic numbers 19-36, including Ga. Therefore, the correct answer is B) Ga.

Question 2

A sample of an element consists of two isotopes. The percent abundance of one of the isotopes is 75.0%. What is the percent abundance of the other isotope?

Accepted Answer

The percent abundances of all isotopes of an element must sum to 100%. If one isotope has a percent abundance of 75.0%, the other must have a percent abundance of 100% - 75% = 25.0%.

Question 3

Which of the following elements is present in the third period of group 7A?

Accepted Answer

Group 7A is also known as Group 17 and consists of nonmetals. The third period includes elements up to sodium (Na) with atomic number 11. Among the options, only option B represents a nonmetal in Group 17, which is chlorine (Cl).

Question 4

Which of the following groups of periodic table contains only nonmetals?

Accepted Answer

The 7A group (also known as Group 17 or the Halogens) contains only nonmetals: fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At).

Question 5

An element consists of three isotopes. The abundance of one isotope is 92.21% and its atomic mass is 27.97693 u. The abundance of the second isotope is 4.70% and its atomic mass is 28.97649 u. The atomic mass of the third isotope is 29.97376 u. What is the atomic weight of the element?

Accepted Answer

The answer of An element consists of three isotopes. The...

Question 6

Copper has an atomic weight of 63.55 u. If 69.17% of copper exists as ⁶³Cu (62.93960 u), what is the identity and the atomic mass of the other isotope?

Accepted Answer

The answer of Copper has an atomic weight of 63.55...

Question 7

Silver has two stable isotopes with masses of 106.90509 u and 108.9047 u. The atomic weight of silver is 107.868 u. What is the percent abundance of each isotope?

Accepted Answer

Let x be the percent abundance of the isotope with mass 106.90509 u. Then, the percent abundance of the isotope with mass 108.9047 u is 100 - x.
Using the atomic weight formula:
(106.90509 u)(x/100) + (108.9047 u)(100 - x)/100 = 107.868 u
Simplifying:
(106.90509x + 108.9047(100 - x))/100 = 107.868
106.90509x + 10890.47 - 108.9047x = 10786.8
-1.99961x = -103.67
x ≈ 51.83
Therefore, the percent abundance of the isotope with mass 106.90509 u is approximately 51.83%, and the percent abundance of the isotope with mass 108.9047 u is approximately 48.17%. Thus, the best choice is B.

Question 8

The masses of isotopes and their abundances are determined experimentally using _____.

Accepted Answer

Mass spectrometry is a technique that is commonly used to determine the mass and relative abundance of isotopes. In a mass spectrometer, ions are created and separated based on their mass-to-charge ratio, which allows for the identification and quantification of different isotopes. Analytical balances are used to measure the mass or weight of substances, but are not used specifically for determining the mass and abundance of isotopes. Centrifuges and distillation are separation techniques used for different purposes, and electrolysis is a process that involves the use of an electric current to bring about a chemical reaction.

Question 9

The element chlorine has two stable isotopes, chlorine-35 with an atomic mass of 34.97 u and chlorine-37 with an atomic mass of 36.97 u. From the atomic weight found on the periodic table, one can conclude that _____.

Accepted Answer

The atomic weight found on the periodic table (35.45 u) is a weighted average of the atomic masses of chlorine-35 and chlorine-37, taking into account their percent natural abundances. Since the atomic weight is closer to the atomic mass of chlorine-35, it can be concluded that chlorine-35 has the highest percent natural abundance.

Question 10

A certain element consists of two stable isotopes. The first has a mass of 14.0031 amu and a percent natural abundance of 99.63%. The second has a mass of 15.001 amu and a percent natural abundance of 0.37%. What is the atomic weight of the element?

Accepted Answer

Atomic weight = (mass of isotope 1 x % abundance of isotope 1/100) + (mass of isotope 2 x % abundance of isotope 2/100)
= (14.0031 amu x 99.63/100) + (15.001 amu x 0.37/100)
= 13.9529863 + 0.055537 = 14.008523 amu
Rounding off to two decimal places, the atomic weight is 14.01 amu. Therefore, the correct answer is C.

Question 11

The elements in groups 1A-8A are known as the _____.

Accepted Answer

The elements in groups 1A-8A are known as the main group elements.

Question 12

Lithium has two naturally occurring isotopes, ⁶Li and ⁷Li. The atomic weight of lithium is 6.941. Which of the following statements concerning the relative abundance of each isotope is correct?

Accepted Answer

The atomic weight of lithium is a weighted average of the isotopes, taking into account their relative abundance. Since the atomic weight is closer to the mass of ⁶Li, it is likely that this isotope is more abundant than ⁷Li. Therefore, answer A is the correct choice.

Question 13

Which of the following elements is present in fourth period of group 3?

Accepted Answer

The answer of Which of the following elements is present...

Question 14

Which of the following statements is true concerning ${ } ^ { 16 } \mathrm { O }$ and ${ } ^ { 17 } \mathrm { O }$ ?

Accepted Answer

Isotopes are atoms of the same element with the same number of protons but different numbers of neutrons. ${ } ^ { 16 } \mathrm { O }$ and ${ } ^ { 17 } \mathrm { O }$ are isotopes of oxygen, differing in their neutron count.

Question 15

Naturally occurring element X exists in three isotopic forms: X-28 (27.979 u, 90.64% abundance), X-29 (28.976 u, 4.00% abundance), and X-30 (29.974 u, 5.36% abundance). Calculate the atomic weight of X.

Accepted Answer

The atomic weight of an element is calculated by multiplying the mass of each isotope by its natural abundance (expressed as a fraction), then summing these products. For element X:- For X-28: $27.979 \, \text{u} \times 0.9064 = 25.351 \, \text{u}$- For X-29: $28.976 \, \text{u} \times 0.04 = 1.159 \, \text{u}$- For X-30: $29.974 \, \text{u} \times 0.0536 = 1.606 \, \text{u}$Adding these together gives the atomic weight of X: $25.351 + 1.159 + 1.606 = 28.116 \, \text{u}$, which rounds to $28.13 \, \text{u}$.

Question 16

Rubidium has two naturally occurring isotopes. The atomic weight of Rb is 85.4678 u. If 72.15% of Rb is found as Rb-85 (84.9117 u), what is the mass of the other isotope?

Accepted Answer

The answer of Rubidium has two naturally occurring isotopes. The...

Question 17

The mass spectrum of an element with two naturally occurring isotopes is shown below. What is the best estimate of the element's (average) atomic weight?

Accepted Answer

The answer of The mass spectrum of an element with...

Question 18

What is the common name of the group that has an element with 38 protons in its nucleus?

Accepted Answer

The group with 38 protons in its nucleus belongs to the alkaline earth metals, which are found in Group 2 of the periodic table.

Question 19

Which of the following elements belongs to the alkaline earth metals series?

Accepted Answer

The alkaline earth metals series includes elements with the atomic numbers 3-12, which include Beryllium, Magnesium, Calcium, Strontium, Barium, and Radium. Out of the options given, only Barium belongs to this series.

Question 20

Which of the following statements is not true about the element vanadium?

Accepted Answer

The answer of Which of the following statements is not...

Quiz 3: Atoms, Molecules, and Ions

Which of the following elements is present in the fourth period of Group 3A?

A sample of an element consists of two isotopes. The percent abundance of one of the isotopes is 75.0%. What is the percent abundance of the other isotope?

Which of the following elements is present in the third period of group 7A?

Which of the following groups of periodic table contains only nonmetals?

An element consists of three isotopes. The abundance of one isotope is 92.21% and its atomic mass is 27.97693 u. The abundance of the second isotope is 4.70% and its atomic mass is 28.97649 u. The atomic mass of the third isotope is 29.97376 u. What is the atomic weight of the element?

Copper has an atomic weight of 63.55 u. If 69.17% of copper exists as ⁶³Cu (62.93960 u) , what is the identity and the atomic mass of the other isotope?

Silver has two stable isotopes with masses of 106.90509 u and 108.9047 u. The atomic weight of silver is 107.868 u. What is the percent abundance of each isotope?

The masses of isotopes and their abundances are determined experimentally using _____.

The element chlorine has two stable isotopes, chlorine-35 with an atomic mass of 34.97 u and chlorine-37 with an atomic mass of 36.97 u. From the atomic weight found on the periodic table, one can conclude that _____.

A certain element consists of two stable isotopes. The first has a mass of 14.0031 amu and a percent natural abundance of 99.63%. The second has a mass of 15.001 amu and a percent natural abundance of 0.37%. What is the atomic weight of the element?

The elements in groups 1A-8A are known as the _____.

Lithium has two naturally occurring isotopes, ⁶Li and ⁷Li. The atomic weight of lithium is 6.941. Which of the following statements concerning the relative abundance of each isotope is correct?

Which of the following elements is present in fourth period of group 3?

Which of the following statements is true concerning ${ } ^ { 16 } \mathrm { O }$ and ${ } ^ { 17 } \mathrm { O }$ ?

Naturally occurring element X exists in three isotopic forms: X-28 (27.979 u, 90.64% abundance) , X-29 (28.976 u, 4.00% abundance) , and X-30 (29.974 u, 5.36% abundance) . Calculate the atomic weight of X.

Rubidium has two naturally occurring isotopes. The atomic weight of Rb is 85.4678 u. If 72.15% of Rb is found as Rb-85 (84.9117 u) , what is the mass of the other isotope?

The mass spectrum of an element with two naturally occurring isotopes is shown below. What is the best estimate of the element's (average) atomic weight?

What is the common name of the group that has an element with 38 protons in its nucleus?

Which of the following elements belongs to the alkaline earth metals series?

Which of the following statements is not true about the element vanadium?

Quiz 3: Atoms, Molecules, and Ions

Which of the following elements is present in the fourth period of Group 3A?

A sample of an element consists of two isotopes. The percent abundance of one of the isotopes is 75.0%. What is the percent abundance of the other isotope?

Which of the following elements is present in the third period of group 7A?

Which of the following groups of periodic table contains only nonmetals?

An element consists of three isotopes. The abundance of one isotope is 92.21% and its atomic mass is 27.97693 u. The abundance of the second isotope is 4.70% and its atomic mass is 28.97649 u. The atomic mass of the third isotope is 29.97376 u. What is the atomic weight of the element?

Copper has an atomic weight of 63.55 u. If 69.17% of copper exists as 63Cu (62.93960 u) , what is the identity and the atomic mass of the other isotope?

Silver has two stable isotopes with masses of 106.90509 u and 108.9047 u. The atomic weight of silver is 107.868 u. What is the percent abundance of each isotope?

The masses of isotopes and their abundances are determined experimentally using _____.

The element chlorine has two stable isotopes, chlorine-35 with an atomic mass of 34.97 u and chlorine-37 with an atomic mass of 36.97 u. From the atomic weight found on the periodic table, one can conclude that _____.

A certain element consists of two stable isotopes. The first has a mass of 14.0031 amu and a percent natural abundance of 99.63%. The second has a mass of 15.001 amu and a percent natural abundance of 0.37%. What is the atomic weight of the element?

The elements in groups 1A-8A are known as the _____.

Lithium has two naturally occurring isotopes, 6Li and 7Li. The atomic weight of lithium is 6.941. Which of the following statements concerning the relative abundance of each isotope is correct?

Which of the following elements is present in fourth period of group 3?

Which of the following statements is true concerning 16O{ } ^ { 16 } \mathrm { O }16O and 17O{ } ^ { 17 } \mathrm { O }17O ?

Naturally occurring element X exists in three isotopic forms: X-28 (27.979 u, 90.64% abundance) , X-29 (28.976 u, 4.00% abundance) , and X-30 (29.974 u, 5.36% abundance) . Calculate the atomic weight of X.

Rubidium has two naturally occurring isotopes. The atomic weight of Rb is 85.4678 u. If 72.15% of Rb is found as Rb-85 (84.9117 u) , what is the mass of the other isotope?

The mass spectrum of an element with two naturally occurring isotopes is shown below. What is the best estimate of the element's (average) atomic weight?

What is the common name of the group that has an element with 38 protons in its nucleus?

Which of the following elements belongs to the alkaline earth metals series?

Which of the following statements is not true about the element vanadium?

Copper has an atomic weight of 63.55 u. If 69.17% of copper exists as ⁶³Cu (62.93960 u) , what is the identity and the atomic mass of the other isotope?

Lithium has two naturally occurring isotopes, ⁶Li and ⁷Li. The atomic weight of lithium is 6.941. Which of the following statements concerning the relative abundance of each isotope is correct?

Which of the following statements is true concerning ${ } ^ { 16 } \mathrm { O }$ and ${ } ^ { 17 } \mathrm { O }$ ?