Question 1

What are the values of Z and A for an atom of silicon that contains 15 neutrons?

Accepted Answer

Silicon has an atomic number (Z) of 14, which is the number of protons. The mass number (A) is the sum of protons and neutrons, so with 15 neutrons, A = 14 (protons) + 15 (neutrons) = 29.

Question 2

Radon - 222 has _____ protons, _____ neutrons, and _____ electrons.

Accepted Answer

Radon-222 has 86 protons (its atomic number), 136 neutrons (222 - 86 = 136), and 86 electrons (equal to the number of protons in a neutral atom).

Question 3

Which of these statements best describes the formation of a cation?

Accepted Answer

A cation is a positively charged ion, which means it has lost one or more electrons from its outer shell. This reduction in electrons leaves the atom with an excess of positively charged protons, giving it a net positive charge. Therefore, choice A is the best description of the formation of a cation.

Question 4

Which scientist is responsible for the organization of the modern periodic table?

Accepted Answer

Dmitri Mendeleev was a Russian chemist who published the first widely recognized periodic table in 1869. His table organized elements based on their atomic mass and chemical properties, and laid the foundation for the modern periodic table.

Question 5

Copper has two naturally occurring isotopes. Cu-63 has a mass of 62.939 amu and Cu-65 has a mass of 64.928 amu. Based on the atomic mass of copper, which isotope has a higher fractional abundance?

Accepted Answer

The atomic mass of copper is the weighted average of the masses of its isotopes, taking into account their natural abundances. So, the higher fractional abundance would correspond to the isotope with the lower mass (Cu-63), which would contribute more to the overall atomic mass of copper. Therefore, Cu-63 has a higher fractional abundance.

Question 6

Carbon has three isotopes: ¹² C, ¹³ C, and ¹⁴ C. If the atomic number of carbon is 6, t hese isotopes each have _____, _____, and _____ neutrons, respectively.

Accepted Answer

The number of neutrons in an isotope is found by subtracting the atomic number (number of protons) from the mass number. For carbon (atomic number 6), the isotopes have 6, 7, and 8 neutrons respectively (12-6=6, 13-6=7, 14-6=8).

Question 7

Isotopes of an element have the same number of _____ but a different number of _____.

Accepted Answer

Isotopes of an element have the same number of protons (which defines the element) but differ in the number of neutrons, leading to different atomic masses.

Question 8

The Ca²⁺ ion contains _____ protons and _____ electrons.

Accepted Answer

The Ca^2+ ion is derived from a calcium atom, which has 20 protons. As a 2+ ion, it has lost 2 electrons, leaving it with 18 electrons.

Question 9

Neon has three isotopes. Assuming the mass of each isotope to be very close to its respective mass number, which isotope is the most abundant based on the atomic mass of neon (Ne)?

Accepted Answer

Neon's atomic mass is approximately 20.18 amu, which is closest to the mass number of Ne-20, indicating that Ne-20 is the most abundant isotope.

Question 10

Mendeleev organized the elements of the periodic table in order of increasing _____.

Accepted Answer

Mendeleev organized the elements in the periodic table by increasing atomic mass, which was the basis for the periodic law in his time.

Question 11

Metals tend to form ions with a positive charge. The most likely way to form a positively charged ion from an atom is by doing which of the following?

Accepted Answer

Metals tend to have few valence electrons, which makes it easier for them to lose these electrons and form a positively charged ion. Gaining protons or losing neutrons would change the identity of the atom, while gaining electrons or losing protons would result in a negatively charged ion.

Question 12

How many protons, electrons, and neutrons are in an ²⁵ Mg ²⁺ ion?

Accepted Answer

The atomic number of magnesium (Mg) is 12, so it has 12 protons. The mass number is 25, so it has 25 - 12 = 13 neutrons. As a 2+ ion, it has lost 2 electrons, leaving it with 10 electrons.

Question 13

Which of these is the correct representation for the ion with Z = 27, A = 60, and C = 2 ⁺ ?

Accepted Answer

The answer of Which of these is the correct representation...

Question 14

Rubidium consists of two naturally occurring isotopes rubidium-85 and rubidium-87. Rubidium-85 (⁸⁵Rb) has an isotopic mass of 84.9117 amu and a 72.15% abundance. Rubidium-87(⁸⁷Rb) has a 27.85% abundance. The atomic weight of rubidium is 85.4768 amu. Determine the isotopic mass of ⁸⁷Rb?

Accepted Answer

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

Question 15

The Cl ⁻ ion contains _____ protons and _____ electrons.

Accepted Answer

The atomic number of chlorine is 17, which means there are 17 protons in the nucleus. The ion, Cl ⁻, has one additional electron compared to the neutral chlorine atom, so it has 18 electrons. Therefore, the correct answer is B, which states that the ion contains 17 protons and 18 electrons.

Question 16

Chlorine has two isotopes, 35Cl and 37Cl, whose respective abundances are 75.77% and 24.23% and masses are 34.9688 amu and 36.9659 amu. Calculate the atomic mass of chlorine.

Accepted Answer

The atomic mass of chlorine can be calculated using the formula:

atomic mass = (abundance of isotope 1 x mass of isotope 1) + (abundance of isotope 2 x mass of isotope 2)

Plugging in the values given:
atomic mass = (0.7577 x 34.9688) + (0.2423 x 36.9659)
atomic mass = 26.4935 + 8.9595
atomic mass = 35.453 amu

Therefore, the atomic mass of chlorine is 35.453 amu, which corresponds to option C.

Question 17

An element has two naturally occurring isotopes. One has an abundance of 37.4% and an isotopic mass of 184.953 amu. The other has an abundance of 62.6% and an isotopic mass  of 186.956 amu. What is the atomic weight of the element?

Accepted Answer

The answer of An element has two naturally occurring isotopes....

Question 18

What are the Z and A values for an atom of krypton that contains 46 neutrons?

Accepted Answer

Krypton has an atomic number (Z) of 36, which represents the number of protons. The mass number (A) is the sum of protons and neutrons, which in this case is 36 (protons) + 46 (neutrons) = 82.

Question 19

How many protons (p), neutrons (n), and electrons (e) are in an atom of ²³⁵U?

Accepted Answer

- S has 1 proton and 1 electron (atomic number)
- U has 1 proton and 1 electron (atomic number) and 235 neutrons (mass number - atomic number)
- P has 1235 protons and 1235 electrons (atomic number) and 143 neutrons (mass number - atomic number)
Therefore, the total number of protons is 92 (1+1+1235+1+1235+1), the total number of neutrons is 143+235=378, and the total number of electrons is 92 (1+1+1235+1+1+1). The only answer choice that matches these values is B.

Question 20

Which of these statements best describes the formation of an anion?

Accepted Answer

An anion is a negatively charged ion which forms when an atom gains one or more electrons. The other options describe the formation of cations, which are positively charged ions that result from the loss of one or more electrons.

Quiz 3: Atoms and Elements

What are the values of Z and A for an atom of silicon that contains 15 neutrons?

Radon - 222 has ___ protons, _ neutrons, and ___ electrons.

Which of these statements best describes the formation of a cation?

Which scientist is responsible for the organization of the modern periodic table?

Copper has two naturally occurring isotopes. Cu-63 has a mass of 62.939 amu and Cu-65 has a mass of 64.928 amu. Based on the atomic mass of copper, which isotope has a higher fractional abundance?

Carbon has three isotopes: ¹² C, ¹³ C, and ¹⁴ C. If the atomic number of carbon is 6, t hese isotopes each have ___, _, and ___ neutrons, respectively.

Isotopes of an element have the same number of _ but a different number of _.

The Ca²⁺ ion contains _ protons and _ electrons.

Neon has three isotopes. Assuming the mass of each isotope to be very close to its respective mass number, which isotope is the most abundant based on the atomic mass of neon (Ne) ?

Mendeleev organized the elements of the periodic table in order of increasing _____.

Metals tend to form ions with a positive charge. The most likely way to form a positively charged ion from an atom is by doing which of the following?

How many protons, electrons, and neutrons are in an ²⁵ Mg ²⁺ ion?

Which of these is the correct representation for the ion with Z = 27, A = 60, and C = 2 ⁺ ?

Rubidium consists of two naturally occurring isotopes rubidium-85 and rubidium-87. Rubidium-85 (⁸⁵Rb) has an isotopic mass of 84.9117 amu and a 72.15% abundance. Rubidium-87(⁸⁷Rb) has a 27.85% abundance. The atomic weight of rubidium is 85.4768 amu. Determine the isotopic mass of ⁸⁷Rb?

The Cl ⁻ ion contains _ protons and _ electrons.

Chlorine has two isotopes, 35Cl and 37Cl, whose respective abundances are 75.77% and 24.23% and masses are 34.9688 amu and 36.9659 amu. Calculate the atomic mass of chlorine.

An element has two naturally occurring isotopes. One has an abundance of 37.4% and an isotopic mass of 184.953 amu. The other has an abundance of 62.6% and an isotopic mass of 186.956 amu. What is the atomic weight of the element?

What are the Z and A values for an atom of krypton that contains 46 neutrons?

How many protons (p) , neutrons (n) , and electrons (e) are in an atom of ²³⁵U?

Which of these statements best describes the formation of an anion?

Quiz 3: Atoms and Elements

What are the values of Z and A for an atom of silicon that contains 15 neutrons?

Radon - 222 has _____ protons, _____ neutrons, and _____ electrons.

Which of these statements best describes the formation of a cation?

Which scientist is responsible for the organization of the modern periodic table?

Copper has two naturally occurring isotopes. Cu-63 has a mass of 62.939 amu and Cu-65 has a mass of 64.928 amu. Based on the atomic mass of copper, which isotope has a higher fractional abundance?

Carbon has three isotopes: 12 C, 13 C, and 14 C. If the atomic number of carbon is 6, t hese isotopes each have _____, _____, and _____ neutrons, respectively.

Isotopes of an element have the same number of _____ but a different number of _____.

The Ca2+ ion contains _____ protons and _____ electrons.

Neon has three isotopes. Assuming the mass of each isotope to be very close to its respective mass number, which isotope is the most abundant based on the atomic mass of neon (Ne) ?

Mendeleev organized the elements of the periodic table in order of increasing _____.

Metals tend to form ions with a positive charge. The most likely way to form a positively charged ion from an atom is by doing which of the following?

How many protons, electrons, and neutrons are in an 25 Mg 2+ ion?

Which of these is the correct representation for the ion with Z = 27, A = 60, and C = 2 + ?

Rubidium consists of two naturally occurring isotopes rubidium-85 and rubidium-87. Rubidium-85 (85Rb) has an isotopic mass of 84.9117 amu and a 72.15% abundance. Rubidium-87(87Rb) has a 27.85% abundance. The atomic weight of rubidium is 85.4768 amu. Determine the isotopic mass of 87Rb?

The Cl − ion contains _____ protons and _____ electrons.

Chlorine has two isotopes, 35Cl and 37Cl, whose respective abundances are 75.77% and 24.23% and masses are 34.9688 amu and 36.9659 amu. Calculate the atomic mass of chlorine.

An element has two naturally occurring isotopes. One has an abundance of 37.4% and an isotopic mass of 184.953 amu. The other has an abundance of 62.6% and an isotopic mass of 186.956 amu. What is the atomic weight of the element?

What are the Z and A values for an atom of krypton that contains 46 neutrons?

How many protons (p) , neutrons (n) , and electrons (e) are in an atom of 235U?

Which of these statements best describes the formation of an anion?

Radon - 222 has ___ protons, _ neutrons, and ___ electrons.

Carbon has three isotopes: ¹² C, ¹³ C, and ¹⁴ C. If the atomic number of carbon is 6, t hese isotopes each have ___, _, and ___ neutrons, respectively.

Isotopes of an element have the same number of _ but a different number of _.

The Ca²⁺ ion contains _ protons and _ electrons.

How many protons, electrons, and neutrons are in an ²⁵ Mg ²⁺ ion?

Which of these is the correct representation for the ion with Z = 27, A = 60, and C = 2 ⁺ ?

Rubidium consists of two naturally occurring isotopes rubidium-85 and rubidium-87. Rubidium-85 (⁸⁵Rb) has an isotopic mass of 84.9117 amu and a 72.15% abundance. Rubidium-87(⁸⁷Rb) has a 27.85% abundance. The atomic weight of rubidium is 85.4768 amu. Determine the isotopic mass of ⁸⁷Rb?

The Cl ⁻ ion contains _ protons and _ electrons.

How many protons (p) , neutrons (n) , and electrons (e) are in an atom of ²³⁵U?