Question 1

Which of the following best explains why sodium (Na), a highly reactive metal, and chlorine (Cl), a poisonous gas, can combine to form table salt (NaCl), which is safe to eat?

Accepted Answer

The combination of sodium and chlorine results in a compound with emergent properties different from those of the individual elements.

Question 2

Which four elements make up approximately 96% of the human body’s mass?

Accepted Answer

Oxygen, carbon, hydrogen, and nitrogen

Question 3

A neutral atom of sodium ($$^{23}_{11}\mathrm{Na}) $$has how many protons, neutrons, and electrons?

Accepted Answer

11 protons, 12 neutrons, 11 electrons

Question 4

Which statement best describes the relationship between electron shells and potential energy?

Accepted Answer

Electrons in shells farther from the nucleus have higher potential energy.

Question 5

How many electrons are found in the first, second, and third shells of a neutral oxygen atom (atomic number 8)?

Accepted Answer

2, 6, 0

Question 6

Which of the following best describes an isotope?

Accepted Answer

Atoms of the same element with different numbers of neutrons

Question 7

What type of bond is formed when one atom transfers an electron to another atom, resulting in oppositely charged ions that attract each other?

Accepted Answer

Ionic bond

Question 8

Which of the following is a trace element required by vertebrates for normal thyroid function?

Accepted Answer

Iodine (I)

Question 9

Which of the following best explains why water is a polar molecule?

Accepted Answer

Oxygen is more electronegative than hydrogen, causing unequal sharing of electrons.

Question 10

Which type of chemical bond is primarily responsible for holding together the two strands of DNA?

Accepted Answer

Hydrogen bonds

Question 11

A gecko can climb smooth walls due to thousands of weak interactions between its toe hairs and the wall surface. What type of interaction is primarily responsible for this phenomenon?

Accepted Answer

Van der Waals interactions

Question 12

Which of the following best describes the role of valence electrons in chemical bonding?

Accepted Answer

They are the electrons in the outermost shell and determine an atom’s chemical behavior.

Question 13

Which of the following molecules is held together by nonpolar covalent bonds?

Accepted Answer

$$\mathrm{O}_2$$

Question 14

What is the molecular shape of methane ($$\mathrm{CH}_4) $$and why?

Accepted Answer

Tetrahedral, because the carbon atom’s orbitals hybridize to form four equivalent bonds at 109.5° angles.

Question 15

Which of the following best describes a hydrogen bond?

Accepted Answer

A weak attraction between a hydrogen atom covalently bonded to an electronegative atom and another electronegative atom.

Question 16

Which of the following is an example of an emergent property?

Accepted Answer

Table salt (NaCl) is edible, while its component elements are toxic.

Question 17

If a radioactive isotope of carbon ($$^{14}\mathrm{C}) $$decays by losing a neutron, what will be the new atomic mass?

Accepted Answer

$$13$$

Question 18

Which of the following best explains why noble gases like neon (Ne) are chemically inert?

Accepted Answer

They have full valence shells.

Question 19

Which of the following best describes the effect of molecular shape on biological function?

Accepted Answer

Molecular shape determines how molecules recognize and interact with each other.

Question 20

Which of the following best describes what happens when sodium and chlorine react to form sodium chloride?

Accepted Answer

Sodium donates an electron to chlorine, forming Na$$^+$$ and Cl$$^-$$ ions that are held together by ionic bonds.

The Chemical Context of Life: Matter, Elements, and Chemical Bonds

스터디 가이드 - 연습 문제

학습 가이드 - 플래시카드