Question 1

Which of the following elements is most abundant in living organisms, making up the majority of biological molecules?

Accepted Answer

Carbon (C)

Question 2

What is the atomic number of an element, and how does it relate to the structure of the atom?

Accepted Answer

It is the number of protons in the nucleus, which determines the element's identity.

Question 3

Which electron shell has the highest energy level for an atom, and how does this affect electron movement?

Accepted Answer

The outermost shell; electrons here have the highest energy and are most likely to be involved in chemical reactions.

Question 4

Given the electron configuration $$1s^2$$ $$2s^2$$ $$2p^6$$ $$3s^2$$ $$3p^4$$, which element does this represent?

Accepted Answer

Sulfur (S)

Question 5

Which of the following best describes a covalent bond?

Accepted Answer

A bond formed by the sharing of electron pairs between atoms.

Question 6

What is the molar mass of glucose ($$C_6H_{12}O_6$)? Use the following atomic masses: C = 12$ g/mol, H = 1$ g/mol, O = 16$ g/mol.

Accepted Answer

$$180 g/$$mol

Question 7

Which statement about valence electrons is correct?

Accepted Answer

Valence electrons are found in the outermost shell and determine chemical reactivity.

Question 8

A molecule of water ($$H_2O) $$has which type of molecular geometry?

Accepted Answer

Bent

Question 9

Which of the following is a correct Lewis dot structure for ammonia ($$NH_3$$)?

Accepted Answer

N with three single bonds to H and one lone pair on N

Question 10

Which of the following ions is formed when sodium reacts with chlorine to produce table salt?

Accepted Answer

$$Na^+$$ and $$Cl^-$$

Question 11

How many electrons are present in a neutral atom of phosphorus ($$P$$), which has an atomic number of $$15$$?

Accepted Answer

$$15$$

Question 12

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

Accepted Answer

They have a full complement of valence electrons, making them stable.

Question 13

What is the correct formula for ammonium chloride?

Accepted Answer

$$NH_4Cl$$

Question 14

Which of the following best describes the difference between ionic and covalent bonds?

Accepted Answer

Ionic bonds involve transferring electrons; covalent bonds involve sharing electrons.

Question 15

If an atom has 17 protons, 18 neutrons, and 17 electrons, what is its atomic mass?

Accepted Answer

$$35$$

Question 16

Which of the following elements is NOT one of the six most common elements in living organisms?

Accepted Answer

Calcium (Ca)

Question 17

What is the electron configuration for a neutral atom of magnesium ($$Mg$$), atomic number $$12$$?

Accepted Answer

$$1s^2$$ $$2s^2$$ $$2p^6$$ $$3s^2$$

Question 18

Which of the following best describes the octet rule?

Accepted Answer

Atoms tend to gain, lose, or share electrons to achieve eight electrons in their outer shell.

Question 19

How many moles are present in $$18$$ grams of water ($$H_2O$$)? (Molar mass of $$H_2O = 18 g/$$mol)

Accepted Answer

$$1$$ mole

Question 20

Which of the following is the correct Lewis dot diagram for carbon dioxide ($$CO_2$$)?

Accepted Answer

O=C=O, with each O having two lone pairs

General Biology: Atomic Structure, Chemical Bonds, and Molecular Properties Study Guide

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