$$6 \times 12 + 12 \times 1 + 6 \times 16 = 180 u$$

Question 1

Which of the following best describes a compound?

Accepted Answer

A homogeneous, pure substance made up of multiple kinds of atoms

Question 2

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

Accepted Answer

Fluorine (F)

Question 3

How many nitrogen (N) atoms are present in 2 molecules of caffeine ($$\mathrm{C_8H_{10}N_4O_2}$$)?

Accepted Answer

8

Question 4

Which of the following is a correct definition of an isotope?

Accepted Answer

Atoms with 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 ($$\mathrm{C_6H_{12}O_6$}$$)? Use atomic weights: C = 12, H = 1, O = 16.

Accepted Answer

$$6 	imes 12 + 12 	imes 1 + 6 	imes 16 = 180 u$$

Question 8

Which of the following elements has the greatest ionization energy?

Accepted Answer

Fluorine (F)

Question 9

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

Accepted Answer

Mg

Question 10

How many valence electrons do calcium (Ca) and strontium (Sr) both 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 is the correct Lewis symbol for sulfur (S)?

Accepted Answer

S with 6 dots

Question 13

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

Accepted Answer

2

Question 14

What ion do you expect potassium (K) to form?

Accepted Answer

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

Question 15

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

Accepted Answer

$$\mathrm{CaO}$$

Question 16

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

Accepted Answer

$$\mathrm{NH_4$^+} ($$ammonium)

Question 17

Which property increases as you move from left to right across a period in the periodic table?

Accepted Answer

Ionization energy

Question 18

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

Accepted Answer

They have a full valence shell of 8 electrons

Question 19

Which of the following statements about ions is correct?

Accepted Answer

A cation has more protons than electrons

Question 20

Which of the following is NOT a main component of biological molecules?

Accepted Answer

Metals

Building Blocks of Molecules: Foundations of GOB Chemistry

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