GRADE 9 2ND PRELIMS REVIEW

What is the electron configuration of oxygen?

• 1s² 2s² 2p⁴

• 1s² 2s² 2p²

• 1s² 2s² 2p³

• 1s² 2s² 2p⁵

How many electrons can the first shell hold?

• 8

• 10

• 2

• 1

What is the significance of valence electrons in bonding?

• Valence electrons are irrelevant in chemical reactions.

• Valence electrons are significant in bonding because they determine how atoms interact and bond with each other.

• Valence electrons are only important in ionic compounds.

• Valence electrons only affect the mass of an atom.

Describe the difference between ionic and covalent bonds.

• Ionic bonds occur only in gases, while covalent bonds occur in solids.

• Covalent bonds are stronger than ionic bonds due to their metallic nature.

• Ionic bonds involve electron transfer and attraction between ions, while covalent bonds involve electron sharing between atoms.

• Ionic bonds are formed by sharing electrons, while covalent bonds involve transferring protons.

What is the electron configuration for sodium?

• 1s² 2s¹ 2p⁶ 3s¹

• 1s² 2s² 2p⁶ 3s²

• 1s² 2s² 2p⁶ 3s¹

• 1s² 2s² 2p⁶ 3p¹

How do you determine the number of valence electrons in an element?

• Valence electrons can be calculated using the element's electron affinity.

• The number of valence electrons is the same for all elements in the same period.

• The number of valence electrons is determined by the atomic mass of the element.

• The number of valence electrons is determined by the group number of the element in the periodic table.

What type of bond is formed between two nonmetals?

• Hydrogen bond

• Metallic bond

• Ionic bond

• Covalent bond

Explain why noble gases are generally unreactive.

• Noble gases readily form compounds with metals.

• Noble gases are generally unreactive due to their complete valence electron shells.

• Noble gases have incomplete valence electron shells.

• Noble gases have high electronegativity, making them reactive.

What is the octet rule in relation to chemical bonding?

• The octet rule states that atoms can only bond with other atoms that have fewer than eight electrons.

• The octet rule is a guideline that atoms prefer to have four electrons in their outermost shell.

• The octet rule indicates that all atoms must have a full outer shell of ten electrons to be stable.

• The octet rule is a principle that atoms seek to have eight electrons in their outermost shell to achieve stability.

How does electronegativity affect bond formation?

• Electronegativity only influences the size of atoms in a molecule.

• Electronegativity has no effect on bond formation.

• Electronegativity determines the color of the bond formed.

• Electronegativity affects bond formation by determining the type of bond (covalent, polar covalent, or ionic) based on the difference in electron attraction between atoms.