$$\text{Atomic weight} - \text{Atomic number}$$

Question 1

Which of the following best describes the organizational levels of the human body, from smallest to largest?

Accepted Answer

Chemical level → Cellular level → Tissue level → Organ level → Organ system level → Organism level

Question 2

Which of the following elements makes up the largest percentage of body mass in humans?

Accepted Answer

Oxygen

Question 3

A molecule of water (H$$_2O) is $$formed by which type of chemical bond between its atoms?

Accepted Answer

Covalent bond

Question 4

Which of the following best explains why sodium (Na) and chlorine (Cl) form an ionic bond in table salt (NaCl)?

Accepted Answer

Sodium transfers an electron to chlorine, resulting in oppositely charged ions that attract each other.

Question 5

Given the atomic number and atomic weight of chlorine are 17 and 35, respectively, how many neutrons does a chlorine atom have?

Accepted Answer

$$35 - 17 = 18$$ neutrons

Question 6

Which of the following statements about isotopes is correct?

Accepted Answer

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

Question 7

Which of the following is NOT a major type of tissue found in the human body?

Accepted Answer

Question 8

If a carbon atom has 4 vacancies in its outermost orbital, how many covalent bonds can it form?

Accepted Answer

4

Question 9

Which chemical group is responsible for the acidic properties of many biological molecules?

Accepted Answer

COOH (carboxyl group)

Question 10

Which of the following best describes a solution in chemistry?

Accepted Answer

A mixture in which solute molecules are permanently and uniformly dispersed among solvent particles.

Question 11

Which of the following is the correct formula for calculating the number of neutrons in an atom?

Accepted Answer

$$	ext{Atomic weight} - 	ext{Atomic number}$$

Question 12

Which of the following best explains why atoms form chemical bonds?

Accepted Answer

To fill vacancies in their outermost electron orbitals and achieve stability.

Question 13

Which of the following statements about ions is correct?

Accepted Answer

An ion is formed when an atom gains or loses electrons, resulting in a net positive or negative charge.

Question 14

Which of the following is a property of electrons?

Accepted Answer

They have a very light mass, approximately $$1/2000$$ AMU.

Question 15

Which of the following is true about covalent bonds?

Accepted Answer

Electrons are shared between atoms.

Question 16

Which of the following best describes a suspension?

Accepted Answer

A mixture consisting of very large particles that settle out due to gravity or other forces.

Question 17

Which of the following elements has 3 bonding sites most commonly available?

Accepted Answer

Nitrogen

Question 18

Which of the following is NOT a subatomic particle found in atoms?

Accepted Answer

Ion

Question 19

Which of the following is a correct statement about the atomic number of an element?

Accepted Answer

It is equal to the number of electrons in a neutral atom.

Question 20

Which of the following is a real-world example of a chemical reaction involving exchange of electrons?

Accepted Answer

Formation of table salt (NaCl) from sodium and chlorine

Unit 1

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