Q: Which pair is both isoelectronic and isotopic?

$$_{20}^{40}\text{Ca}^{2+}$$ and $$_{18}^{40}\text{Ar}$$

Question 1

Which of the following statements about subatomic particles is correct?

Accepted Answer

Protons and electrons have charges of the same magnitude but opposite signs.

Question 2

Which force is responsible for holding protons and neutrons together in the nucleus?

Accepted Answer

Nuclear force

Question 3

Osmium has an actual mass of 190.23 grams. What is its value in atomic mass units (Da)? $$1 	ext{ amu} = 1.66054 	imes 10$$^{-24}$$ 	ext{ g}$$

Accepted Answer

$$1.15 	imes 10$$^{26}$$ Da

Question 4

Which conclusion did Rutherford draw from his gold foil experiment?

Accepted Answer

Protons are not evenly distributed throughout an atom.

Question 5

How many neutrons are in the isotope $$_{20}^{43}	ext{Ca}$$?

Accepted Answer

23

Question 6

Which pair is both isoelectronic and isotopic?

Accepted Answer

$$_{20}^{40}	ext{Ca}^{2+}$$ and $$_{18}^{40}	ext{Ar}$$

Question 7

Which of the following is a metalloid?

Accepted Answer

Si

Question 8

Which element is a representative element, found in the 3rd Period, that is also a pnictogen?

Accepted Answer

P

Question 9

Which of the following is a homonuclear polyatomic element?

Accepted Answer

Selenium

Question 10

Which of the following elements is a nonmetal that is a homonuclear polyatomic solid at room temperature?

Accepted Answer

Sulfur

Question 11

Calculate the molar mass of $$	ext{NiCl}_2 \cdot 6	ext{H}_2	ext{O} ($$nickel(II) chloride hexahydrate). (Atomic masses: Ni = 58.69, Cl = 35.45, H = 1.008, O = 16.00)

Accepted Answer

$$237.72\ 	ext{g/mol}$$

Question 12

How many moles of chlorine gas are there in $$8.33 	imes 10$$^{37}$$ molecules? (1$$\ 	ext{mol} = 6.022 	imes $$10^{23}$$ molecules)

Accepted Answer

$$1.38 	imes 10$$^{14}$$ mol

Question 13

Which of the following is an example of the Law of Multiple Proportions?

Accepted Answer

Two different compounds formed from carbon and oxygen have the following mass ratios: 1.33 g O to 1 g C and 2.66 g O to 1 g C.

Question 14

Which of the following species has bonds with the most ionic character?

Accepted Answer

SnO$$_2$$

Question 15

Which of the following is NOT a physical property attributed to metallic bonding?

Accepted Answer

Brittleness

Question 16

What is the systematic name for the polyatomic ion NO$$_2^-$$?

Accepted Answer

Nitrite

Question 17

What is the correct name for the compound Al(BrO$$_4$$)$$_3$$?

Accepted Answer

Aluminum perbromate

Question 18

Which of the following compounds would NOT be associated with the term 'formula unit'?

Accepted Answer

CH$$_3$$COONa

Question 19

Which of the following statements is NOT a component of Dalton’s Atomic Theory?

Accepted Answer

Atoms are composed of protons, neutrons, and electrons.

Atoms, Molecules, and Ions: Foundations of General Chemistry

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