Question 1

An element's most stable ion forms an ionic compound with chlorine having the formula XCl₂.If the ion of element X has a mass number of 89 and 36 electrons,what is the identity of the element X,and how many neutrons does it have?

Accepted Answer

The element X forms an ion with 36 electrons, which means its atomic number is 36, identifying it as krypton (Kr) in its neutral state. However, since the ion has a mass number of 89 and given that the atomic number (number of protons) for Kr is actually 36, the element in question must be strontium (Sr) because the atomic number fits the electron count for its most stable ion. Strontium's atomic number is 38, but as an ion with 36 electrons, it has lost 2 electrons, indicating it is in a +2 oxidation state, which matches the properties of strontium ions. To find the number of neutrons, subtract the atomic number from the mass number: 89 - 38 = 51 neutrons.

Question 2

Write the symbol and the number of neutrons for an element with atomic number 26 and mass number 56.

Accepted Answer

The answer of Write the symbol and the number of...

Question 3

The chemical formula Ga₂O₃ indicates

Accepted Answer

The formula Ga2O3 indicates two atoms of gallium (Ga) and three atoms of oxygen (O), matching choice A.

Question 4

Positron emission by polonium-207 results in the formation of _____.(Atomic number of polonium = 84)

Accepted Answer

Positron emission decreases the atomic number by 1. So, the atomic number of the product will be 84-1 = 83. Bismuth has an atomic number of 83. Therefore, the correct answer is A: bismuth-201.

Question 5

Which of the following statements are true? I.The number of protons in an element is the same for all neutral atoms of that element.
II)The number of electrons in an element is the same for all neutral atoms of that element.
III)The number of neutrons in an element is the same for all neutral atoms of that element.

Accepted Answer

I and II are true because the number of protons defines the element, and in a neutral atom, the number of electrons equals the number of protons. III is false because isotopes of an element have different numbers of neutrons.

Question 6

The mass number of an atom is equal to _____.

Accepted Answer

The mass number of an atom is equal to the sum of the number of protons and the number of neutrons per atom, which is represented by the symbol A. This is because the mass number is a measure of the total number of particles (protons and neutrons) in the nucleus of an atom. Therefore, choice D is the best choice as it correctly describes the definition of mass number.

Question 7

The number of neutrons in one atom of  is

Accepted Answer

The answer of The number of neutrons in one atom...

Question 8

The average mass of a boron atom is 10.81.Assuming you were able to isolate only one boron atom,the chance that you would randomly get one with a mass of 10.81 is

Accepted Answer

The average atomic mass of boron (10.81) is a weighted average of the masses of its isotopes, not the mass of any individual atom. Individual boron atoms can only have the mass of one of its isotopes, not an average, so the chance of getting an atom with exactly 10.81 u is 0%.

Question 9

How many neutrons are there in one atom of  ?

Accepted Answer

The atomic number of the element is 11, which means it has 11 protons in its nucleus. The given symbol has a mass number of 24, which represents the sum of protons and neutrons in the nucleus. Therefore, the number of neutrons in the nucleus would be 24 - 11 = 13. Hence, the correct answer is B.

Question 10

Determine the number of protons and neutrons in Cu-63.

Accepted Answer

The answer of Determine the number of protons and neutrons...

Question 11

A certain ion X³⁺ contains 28 electrons and 37 neutrons.What is the mass number of this ion?

Accepted Answer

The mass number is the sum of the number of protons and neutrons in the nucleus. The ion X³⁺ has 28 electrons, which means it has 28 protons. It also has 37 neutrons. Therefore, the mass number of the ion is 28 + 37 = 65.

Question 12

The atom with 69 neutrons and 50 protons has a mass number of

Accepted Answer

The mass number of an atom is the sum of the number of protons and the number of neutrons. Therefore, mass number = 69 + 50 = 119. The correct choice is D.

Question 13

An atom with 15 protons and 16 neutrons is an atom of

Accepted Answer

An atom is defined by its number of protons, which determines its element. An atom with 15 protons corresponds to phosphorus (P) on the periodic table.

Question 14

Which particle has the smallest mass?

Accepted Answer

The electron has the smallest mass of these options. Neutrons and protons have roughly the same mass and are much larger than electrons. Helium nuclei, also known as alpha particles, have a mass four times that of a proton or neutron.

Question 15

How many protons,electrons,and neutrons,respectively,does ⁵⁸Fe have?

Accepted Answer

Fe (iron) has an atomic number of 26, which means it has 26 protons and, in a neutral atom, 26 electrons. The mass number is 158, and subtracting the number of protons (26) from the mass number gives the number of neutrons, which is 32 (158 - 126 = 32).

Question 16

Which atomic particle determines the chemical behavior of an atom?

Accepted Answer

The electron determines the chemical behavior of an atom because it is involved in chemical bonding and determines the atom's reactivity.

Question 17

The first scientist to develop the theory that all atoms of a given element are identical was

Accepted Answer

John Dalton developed the theory of atomic theory in 1803, which stated that all atoms of a given element are identical in size, mass, and other properties.

Question 18

How many protons,electrons,and neutrons,respectively,does  have?

Accepted Answer

The answer of How many protons,electrons,and neutrons,respectively,does  have?
...

Question 19

How many protons,electrons,and neutrons,respectively,does ⁴⁰Ca²⁺ have?

Accepted Answer

The given symbol represents a calcium ion with a charge of +2 (Ca^2+). Calcium (Ca) has an atomic number of 20, which means it has 20 protons and, in its neutral state, 20 electrons. However, since it has a +2 charge, it has lost 2 electrons, leaving it with 18 electrons. The mass number (P) is 40, which is the sum of protons and neutrons. Therefore, to find the number of neutrons: 40 (mass number) - 20 (protons) = 20 neutrons.

Question 20

List the three main subatomic particles.

Accepted Answer

The answer of List the three main subatomic particles....

Quiz 26: Nuclear Chemistry

An element's most stable ion forms an ionic compound with chlorine having the formula XCl2.If the ion of element X has a mass number of 89 and 36 electrons,what is the identity of the element X,and how many neutrons does it have?

Write the symbol and the number of neutrons for an element with atomic number 26 and mass number 56.

The chemical formula Ga2O3 indicates