Chemistry Test: Unit6 Chemical Bonding Review

The electrons found in the outermost shell of an atom are called:

• Core electrons

• Valence electrons

• Free electrons

• Bound electrons

Answer explanation

The electrons in the outermost shell of an atom are known as valence electrons. They play a crucial role in chemical bonding and determine the reactivity of the element.

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

Which element has the atomic number 6?

• Oxygen

• Nitrogen

• Carbon

• Helium

Answer explanation

The atomic number 6 corresponds to Carbon, which is a fundamental element in organic chemistry. Oxygen (8), Nitrogen (7), and Helium (2) have different atomic numbers.

Tags

NGSS.MS-PS1-1

The rule stating that atoms tend to form bonds to have eight electrons in their valence shell is called:

• Duet rule

• Octet rule

• Valence rule

• Bonding rule

Answer explanation

The octet rule states that atoms form bonds to achieve a full valence shell of eight electrons, which is a stable configuration. This is crucial for understanding chemical bonding and reactivity.

A positively charged ion formed when an atom loses electrons is a:

• Anion

• Cation

• Neutron

• Proton

Answer explanation

A cation is a positively charged ion formed when an atom loses electrons. In contrast, an anion is negatively charged, while neutrons and protons are subatomic particles, not ions.

The most abundant element in the universe is:

• Oxygen

• Hydrogen

• Nitrogen

• Helium

Answer explanation

Hydrogen is the most abundant element in the universe, making up about 75% of its elemental mass. It is the primary building block for stars and galaxies, far surpassing other elements like oxygen, nitrogen, and helium.

The chemical symbol for sodium is:

• S

• Na

• K

• Si

Answer explanation

The chemical symbol for sodium is 'Na', derived from its Latin name 'Natrium'. 'S' stands for sulfur, 'K' for potassium, and 'Si' for silicon, making 'Na' the correct choice.

An ion with a negative charge is called an:

• Anion

• Cation

• Proton

• Neutron

Answer explanation

An ion with a negative charge is called an anion. This is because anions are formed when atoms gain electrons, resulting in a net negative charge. In contrast, cations are positively charged ions.

Bonds that involve the sharing of electrons between atoms are:

• Ionic bonds

• Covalent bonds

• Metallic bonds

• Hydrogen bonds

Answer explanation

Covalent bonds involve the sharing of electrons between atoms, allowing them to achieve stability. In contrast, ionic bonds involve the transfer of electrons, metallic bonds involve a sea of shared electrons, and hydrogen bonds are weak attractions.

Tags

NGSS.HS-PS1-1

Which table organizes elements based on their atomic number and chemical properties?

• Covalent Table

• Ionic Table

• Periodic Table

• Element Table

Answer explanation

The Periodic Table organizes elements by their atomic number and groups them based on similar chemical properties, making it a fundamental tool in chemistry. The other options do not serve this purpose.

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NGSS.HS-PS1-1

The process of gaining electrons is called:

• Oxidation

• Reduction

• Ionization

• Polarization

Answer explanation

The process of gaining electrons is called reduction. In contrast, oxidation refers to the loss of electrons. Therefore, the correct answer is reduction.

Tags

NGSS.HS-PS1-1