Question 1

Which of the following statements correctly describes the charge, mass, and location of a neutron in an atom?

Accepted Answer

Charge: $$0$$, Mass: $$1$$ amu, Location: Nucleus

Question 2

A neutral atom of chlorine has an atomic number of $$17$$ and a mass number of $$35. $$How many protons, neutrons, and electrons does it contain?

Accepted Answer

Protons: $$17$$, Neutrons: $$18$$, Electrons: $$17$$

Question 3

Given the following isotopes of magnesium: $$^{24}\mathrm{Mg} (78.99$$%, mass = $$23.985$$ amu), $$^{25}\mathrm{Mg} (10.00$$%, mass = $$24.986$$ amu), and $$^{26}\mathrm{Mg} (11.01$$%, mass = $$25.983$$ amu), calculate the average atomic mass of magnesium.

Accepted Answer

$$24.31$$ amu

Question 4

Which of the following elements is a metalloid (semimetal)?

Accepted Answer

Silicon ($$\mathrm{Si})$$

Question 5

Which element in the following set has the largest atomic radius: $$\mathrm{Na}$$, $$\mathrm{Mg}$$, $$\mathrm{Al}$$, $$\mathrm{Si}$$?

Accepted Answer

$$\mathrm{Na}$$

Question 6

Which of the following elements has the highest first ionization energy?

Accepted Answer

$$\mathrm{Ne}$$

Question 7

What is the abbreviated electron configuration for $$\mathrm{Ca}^{2+} ($$calcium ion)?

Accepted Answer

$$[\mathrm{Ar}]$$

Question 8

Which group on the periodic table is known as the alkali metals?

Accepted Answer

Group $$1$$

Question 9

How many valence electrons does a phosphorus atom ($$\mathrm{P}$$, atomic number $$15) $$have?

Accepted Answer

$$5$$

Question 10

Which of the following is the correct formula for ammonium sulfate?

Accepted Answer

$$(\mathrm{NH}_4)_2\mathrm{SO}_4$$

Question 11

Which of the following molecules is polar?

Accepted Answer

$$\mathrm{H}_2\mathrm{O}$$

Question 12

What is the molecular geometry of methane ($$\mathrm{CH}_4) $$according to VSEPR theory?

Accepted Answer

Tetrahedral

Question 13

Which of the following compounds contains both ionic and covalent bonds?

Accepted Answer

$$\mathrm{NaNO}_3$$

Question 14

Which of the following intermolecular forces is the strongest?

Accepted Answer

Hydrogen bonding

Question 15

Which of the following ions has the same electron configuration as argon ($$\mathrm{Ar}$$)?

Accepted Answer

$$\mathrm{Cl}^-$$

Question 16

Which of the following best describes the trend in first ionization energy across a period from left to right?

Accepted Answer

It increases

Question 17

Which of the following is the correct Lewis electron-dot structure for carbon dioxide ($$\mathrm{CO}_2$$)?

Accepted Answer

$$\mathrm{O}=\mathrm{C}=\mathrm{O}$$, with each O atom having two lone pairs

Question 18

Which of the following best explains why fluorine has a higher electron affinity than lithium?

Accepted Answer

Fluorine has a greater nuclear charge and a smaller atomic radius, increasing its attraction for electrons.

Question 19

Which of the following is the correct name for $$\mathrm{P}_2\mathrm{O}_5$$?

Accepted Answer

Diphosphorus pentoxide

Question 20

A patient is given a saline solution containing $$0.9\%$$ $$\mathrm{NaCl} by $$mass. Which type of attractive force is primarily responsible for holding the $$\mathrm{Na}^+$$ and $$\mathrm{Cl}^-$$ ions together in solid sodium chloride?

Accepted Answer

Ionic bonds

Atomic Structure, Periodic Trends, and Chemical Bonding: Step-by-Step Study Guidance

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