Question 1

Which of the following best describes a compound?

Accepted Answer

A pure substance made up of two or more different kinds of atoms chemically bonded together.

Question 2

Which element is NOT found in significant amounts in the human body?

Accepted Answer

Fluorine (F)

Question 3

How many nitrogen (N) atoms are present in two molecules of caffeine ($$\mathrm{C_8H_{10}N_4O_2}$$)?

Accepted Answer

$$8$$

Question 4

Which of the following statements about isotopes is correct?

Accepted Answer

Isotopes have the same number of protons but different numbers of neutrons.

Question 5

A neutral atom of technetium-99 ($$^{99}_{43}\mathrm{Tc}) $$contains how many protons, neutrons, and electrons?

Accepted Answer

$$43$$\ protons,\ 56\ neutrons,\ 43\ electrons$

Question 6

Which numbers are identical for the neutral isotopes carbon-12 and carbon-14?

Accepted Answer

Atomic number, number of protons, number of electrons

Question 7

What is the molecular weight of glucose ($$\mathrm{C_6H_{12}O_6$}$$)? (Atomic weights: C = 12, H = 1, O = 16)

Accepted Answer

$$180\ \mathrm{u}$$

Question 8

Which of the following elements is the largest in atomic size?

Accepted Answer

Mg

Question 9

Which element has the greatest ionization energy?

Accepted Answer

F

Question 10

How many valence electrons do calcium (Ca) and strontium (Sr) have?

Accepted Answer

Two ($$s^2)$$

Question 11

According to the octet rule, how many more electrons does sulfur (S) need to fill its valence shell?

Accepted Answer

2

Question 12

Which of the following best describes why noble gases are generally unreactive?

Accepted Answer

They have a full valence shell of 8 electrons ($$s^2p^6$).

Question 13

What ion does potassium (K) most likely form?

Accepted Answer

$$1+$$ ($$\mathrm{K^+})$$

Question 14

Which of the following is a polyatomic ion commonly found in biological systems?

Accepted Answer

$$\mathrm{SO_4$^{2-}} ($$sulfate)

Question 15

What is the correct formula for the binary ionic compound formed between calcium (Ca) and oxygen (O)?

Accepted Answer

$$\mathrm{CaO}$$

Question 16

Which of the following best explains why strontium (Sr) can replace calcium (Ca) in bones?

Accepted Answer

They have the same number of valence electrons.

Question 17

Which of the following is true about cations?

Accepted Answer

They have more protons than electrons.

Question 18

Which of the following best describes the trend in atomic size across a period (left to right) in the periodic table?

Accepted Answer

Atomic size decreases due to increased nuclear charge.

Question 19

Which of the following is the correct Lewis symbol for sulfur (S)?

Accepted Answer

S with 6 dots

Question 20

How many covalent bonds does sulfur (S) typically form to fill its octet?

Accepted Answer

2

Lecture 1: Building Blocks of Molecules

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