Q: Which equation correctly calculates the atomic weight ($AW$) of an element with two isotopes, given their masses ($M_1$, $M_2$) and fractional abundances ($f_1$, $f_2$)?

$AW = (M_1 \times f_1) + (M_2 \times f_2)$

Q: A chlorine atom has two common isotopes: $^{35}Cl$ (75.77% abundance, atomic mass 34.969 amu) and $^{37}Cl$ (24.23% abundance, atomic mass 36.966 amu). What is the atomic weight of chlorine?

$AW = (34.969 \times 0.7577) + (36.966 \times 0.2423) = 35.45$

Question 1

According to Dalton's Atomic Theory, which statement is FALSE?

Accepted Answer

Atoms of a given element are identical, whereas atoms of different elements are different.

Question 2

Which of the following best describes an isotope?

Accepted Answer

Atoms with the same atomic number but different mass numbers.

Question 3

A neutral atom of $^{75}_{33}As$ has how many protons, neutrons, and electrons?

Accepted Answer

33 protons, 42 neutrons, 33 electrons

Question 4

Which equation correctly calculates the atomic weight ($AW$) of an element with two isotopes, given their masses ($M_1$, $M_2$) and fractional abundances ($f_1$, $f_2$)?

Accepted Answer

$AW = (M_1 	imes f_1) + (M_2 	imes f_2)$

Question 5

An atom of mercury has 80 protons and 122 neutrons. What is its atomic nuclear symbol?

Accepted Answer

$^{202}_{80}Hg$

Question 6

Which of the following statements about ions is correct?

Accepted Answer

Cations are formed by the loss of electrons.

Question 7

A chlorine atom has two common isotopes: $^{35}Cl$ (75.77% abundance, atomic mass 34.969 amu) and $^{37}Cl$ (24.23% abundance, atomic mass 36.966 amu). What is the atomic weight of chlorine?

Accepted Answer

$AW = (34.969 	imes 0.7577) + (36.966 	imes 0.2423) = 35.45$

Question 8

Which of the following best explains why sodium forms a positive ion when it loses an electron?

Accepted Answer

Losing an electron increases the number of protons relative to electrons, resulting in a net positive charge.

Question 9

A $^{24}_{12}Mg^{2+}$ ion has how many protons, neutrons, and electrons?

Accepted Answer

12 protons, 12 neutrons, 10 electrons

Question 10

Which of the following is TRUE about compounds according to Dalton's Atomic Theory?

Accepted Answer

Compounds are formed by the union of two or more elements in a fixed proportion by mass.

Question 11

Which of the following atoms is an isotope of $^{14}_{6}C$?

Accepted Answer

$^{13}_{6}C$

Question 12

A $^{32}S^{2-}$ ion has how many electrons?

Accepted Answer

18 electrons

Question 13

Which of the following best describes the difference between a cation and an anion?

Accepted Answer

A cation is formed by losing electrons, while an anion is formed by gaining electrons.

Question 14

If an atom has 20 protons, 18 electrons, and a mass number of 40, what is its atomic nuclear symbol?

Accepted Answer

$^{40}_{20}Ca^{2+}$

Question 15

Which of the following is NOT a property of isotopes?

Accepted Answer

Isotopes of the same element have different atomic numbers.

Question 16

A $^{7}_{3}Li^{+}$ ion has how many neutrons?

Accepted Answer

4 neutrons

Question 17

Which of the following best explains why metals tend to form cations?

Accepted Answer

Metals tend to lose electrons in chemical reactions, resulting in a positive charge.

Question 18

Which of the following is the correct calculation for the number of neutrons in $^{48}_{22}Ti$?

Accepted Answer

$48 - 22 = 26$ neutrons

Question 19

Which of the following best describes the relationship between atomic number and the identity of an element?

Accepted Answer

The atomic number is equal to the number of protons and determines the element.

Fundamentals of Atomic Structure: Atoms, Isotopes, Atomic Weights, and Ions

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