Chapter 1-8 Chemistry Practice: Covalent Bonds, Polarity, and Ions

Flashcards cover octet rule, diatomic molecules, bond types (single/double/triple), polarity and electronegativity, hydrophobic effect, ionic vs covalent bonding, and behavior of ions in water, as discussed across Chapters 1–8.

What is the octet rule in covalent bonding?

The goal is to have eight electrons in the outermost shell, giving stability like a noble gas.

What does diatomic mean and can you name an example mentioned in the notes?

Diatomic means two atoms bonded together; a notable example is H2 (molecular hydrogen).

How many bonds does an atom in group 5 typically form to reach eight electrons, and what are the possible bond combinations?

Typically three bonds; combinations can be three single bonds, or one triple bond, or one double plus one single bond.

Define a polar covalent bond.

A bond where electrons are shared unequal between two atoms, leading to partial charges (δ− and δ+).

What is electronegativity and how does it trend on the periodic table?

Electronegativity is the tendency to attract electrons; it increases to the right and up on the periodic table; fluorine is the most electronegative.

How can you determine if a bond is polar based on electronegativity differences?

If the difference is about 0.5 or greater, the bond is polar; if less, it’s nonpolar.

What is meant by a polar molecule’s interaction with water?

Polar molecules dissolve in polar solvents like water due to dipole interactions.

What are electrostatic interactions between polar molecules called?

Dipole–dipole interactions, where opposite partial charges attract between molecules.

What is the hydrophobic effect?

The tendency of nonpolar molecules to cluster in water to minimize contact with water, aiding processes like protein folding, without energy input.

What is an ion?

An atom or molecule that exists with a net electric charge because it gained or lost electrons.

How does an ion form by electron transfer?

An atom loses electrons to become a positively charged cation or gains electrons to become a negatively charged anion, aiming for an octet.

What is a cation?

A positively charged ion formed when an atom loses electrons.

What is an anion?

A negatively charged ion formed when an atom gains electrons.

Why is Na+ considered stable and what noble-gas-like configuration does it resemble?

Na+ has a neon-like configuration (2s2 2p6) with eight electrons in the outer shell of the second level, giving stability.

Do left-side (metal) elements tend to lose or gain electrons, and what about right-side elements?

Left-side metals tend to lose electrons (form cations); right-side nonmetals tend to gain electrons (form anions).

What is NaCl and how does it behave in water?

NaCl is an ionic compound (salt) that dissociates in water into Na+ and Cl− ions.

What is an ionic bond?

A bond formed by transfer of electrons that yields electrostatic attraction between oppositely charged ions.

Which type of substance is more likely to be polar: carbon-oxygen vs carbon-hydrogen?

Carbon–oxygen bonds are more polar than carbon–hydrogen bonds due to greater electronegativity difference.

How do polar and nonpolar substances behave in water versus nonpolar solvents like oil?

Polar substances dissolve in water; nonpolar substances (like oil) do not mix with water and tend to separate.

What is the difference between a polar bond and a polar molecule with zero net polarity?

A molecule can have polar bonds but overall zero polarity if the dipoles cancel due to molecular geometry (e.g., some symmetrical arrangements).

What is meant by the delta notation (δ− and δ+) in polar bonds?

δ− indicates partial negative charge and δ+ indicates partial positive charge on atoms in a polar covalent bond.

What is the general rule for predicting polarity using electronegativity differences without memorizing exact values?

Compare the two atoms: the bond to the more electronegative atom (further right/up) is more polar; larger differences yield more polar bonds.

What happens to salts like NaCl when dissolved in water?

Salts dissociate into their ions (Na+ and Cl−) in water.