Unit 4/5-Covalent Bonding/Nomenclature

Electrons involved in bonding between atoms are

• valence electrons

• inside the nucleus

• closest to the nucleus

• positively charged

Answer explanation

Electrons involved in bonding between atoms are called valence electrons. They are located in the outermost shell of an atom and are responsible for forming chemical bonds, unlike electrons inside the nucleus or those closest to it.

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

A chemical bond formed when two atoms share electrons is called a(n)

• ionic bond

• covalent bond

• polyatomic bond

• crystal bond

Answer explanation

A chemical bond formed when two atoms share electrons is called a covalent bond. In contrast, ionic bonds involve the transfer of electrons, while polyatomic and crystal bonds refer to different bonding scenarios.

The pair of elements that forms a covalent bond is

• Na and Cl.

• C and O.

• Li and Br.

Answer explanation

C and O form a covalent bond by sharing electrons, while Na and Cl and Li and Br typically form ionic bonds due to their electronegativity differences. Thus, C and O is the correct choice.

Which of these form a nonpolar covalent bond?

• Na and F.

• O and O.

• K and Cl.

Answer explanation

O and O form a nonpolar covalent bond because they are identical atoms sharing electrons equally. In contrast, Na and F, and K and Cl form polar bonds due to the difference in electronegativity.

Tags

NGSS.HS-PS1-1

Due to its 2 lone pairs , H₂O has a ______ molecular geometry.

• tetrahedral

• Trigonal Planar

• bent

• trigonal pyramidal

Answer explanation

H2O has two lone pairs of electrons on the oxygen atom, which repel the bonding pairs. This results in a bent molecular geometry, rather than tetrahedral or trigonal pyramidal, making 'bent' the correct choice.

Is CCl₄ polar or nonpolar molecule?

• polar ( non Symmetrical)

• nonpolar ( Symmertical)

Answer explanation

CCl4 is a symmetrical molecule with a tetrahedral shape, causing the dipole moments of the C-Cl bonds to cancel out. Therefore, CCl4 is nonpolar.

Tags

NGSS.HS-PS1-2

This image shows the bonding between Lithium and Fluorine. What does the red arrow show?

• electrons being shared

• electrons being transferred to Fluorine

• electrons being transferred to Lithium

• electrons being destroyed

Answer explanation

The red arrow indicates that electrons are being transferred from Lithium to Fluorine. This transfer occurs because Fluorine is more electronegative, attracting the electron to form an ionic bond.

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

What two types of atoms make a covalent bond?

• 2 Nonmetals

• 1 Nonmetal and 1 Metal

• 2 Metals

• 2 Noble Gases

Answer explanation

Covalent bonds form when two nonmetals share electrons. This sharing allows both atoms to achieve a full outer shell, which is a stable configuration. Therefore, the correct answer is 2 Nonmetals.

How many electrons are shared in a single bond?

• 2 pairs

• 4

• 2

• 1

Answer explanation

In a single bond, 2 electrons are shared between two atoms. This is the fundamental characteristic of a covalent bond, making the correct answer 2.

Which of the following is the correct Lewis dot structure for the molecule fluorine (F₂)?

• A

• B

• C

• D

Answer explanation

The correct Lewis dot structure for fluorine (F2) is choice B, which shows two fluorine atoms sharing a pair of electrons. Each fluorine atom has three lone pairs and one bond, representing the diatomic nature of F2.

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2