Biology Chapter on Elements and Molecules

<p>Isotopes (B)</p> Signup and view all the answers

<p>It has more protons than electrons, resulting in a positive charge. (C)</p> Signup and view all the answers

<p>They spontaneously decay, emitting particles and energy. (C)</p> Signup and view all the answers

<p>The sum of protons and neutrons in the nucleus. (A)</p> Signup and view all the answers

<p>Calcium (B)</p> Signup and view all the answers

<p>To maintain a stable pH by binding or releasing H+ ions. (B)</p> Signup and view all the answers

<p>Its electron configuration that allows it to form covalent bonds with multiple elements. (B)</p> Signup and view all the answers

<p>They can vary in length, shape, and bonding patterns. (C)</p> Signup and view all the answers

<p>They are components that are involved in the chemical reactions and determine the unique characteristics of a molecule. (C)</p> Signup and view all the answers

<p>The distribution of electrons in its electron shells (A)</p> Signup and view all the answers

<p>They differ in the type and arrangement of functional groups attached to the carbon rings. (B)</p> Signup and view all the answers

<p>Valence electrons (B)</p> Signup and view all the answers

<p>2 (D)</p> Signup and view all the answers

<p>Sharing of a pair of valence electrons between two atoms (A)</p> Signup and view all the answers

<p>All compounds are molecules, but not all molecules are compounds. (C)</p> Signup and view all the answers

<p>The bonding capacity of an atom (B)</p> Signup and view all the answers

<p>Unequal sharing of electrons due to electronegativity differences (D)</p> Signup and view all the answers

<p>Polar bonds involve unequal sharing of electrons due to differences in electronegativity, whereas nonpolar bonds involve equal sharing. (C)</p> Signup and view all the answers

<p>Ionic bond (B)</p> Signup and view all the answers

<p>The ratio of ions in the crystal lattice (A)</p> Signup and view all the answers

<p>A hydrogen atom covalently bonded to an electronegative atom and attraction to another electronegative atom (D)</p> Signup and view all the answers

<p>Van der Waals interactions (C)</p> Signup and view all the answers

<p>Its polarity and capacity to form hydrogen bonds. (B)</p> Signup and view all the answers

<p>Reactants (A)</p> Signup and view all the answers

<p>Hydrophobic (B)</p> Signup and view all the answers

<p>When the forward and reverse reactions occur at the same rate (C)</p> Signup and view all the answers

<p>A hydronium ion (H3O+) (A)</p> Signup and view all the answers

<p>7 (B)</p> Signup and view all the answers

<p>Because of the highly electronegative oxygen atoms causing an uneven charge distribution (B)</p> Signup and view all the answers

<p>To minimize changes in the concentrations of H+ and OH−. (B)</p> Signup and view all the answers

<p>The number of atoms (C)</p> Signup and view all the answers

<p>$NH_3 + H^+ \rightarrow NH_4^+$ (C)</p> Signup and view all the answers

<p>Hydrogen bond (D)</p> Signup and view all the answers

<p>It is acidic. (D)</p> Signup and view all the answers

A substance that cannot be broken down into simpler substances by chemical reactions.

The smallest unit of matter that retains the properties of an element.

The number of protons in an atom's nucleus.

The sum of protons and neutrons in an atom's nucleus.

Atoms of the same element that have the same number of protons but different numbers of neutrons.

An atom or molecule with a net electrical charge due to the gain or loss of electrons.

The potential energy that an electron possesses.

The formation and function of molecules depend on the chemical bonds between atoms that connect them.

An atom's ability to attract shared electrons in a covalent bond.

Atoms share electrons equally. Example: H-H

Atoms share electrons unequally, creating partial positive and negative charges. Example: Water (H2O)

Weak chemical bonds (e.g., hydrogen bonds) that play a crucial role in the function of molecules.

The sharing of a pair of valence electrons by two atoms.

Two or more atoms held together by covalent bonds.

A combination of two or more different elements held together by covalent bonds.

The number of covalent bonds an atom can form. Example: Hydrogen has a valence of 1, Oxygen has a valence of 2.

A chemical bond formed by the attraction between oppositely charged ions. It arises when one atom donates an electron to another, creating a positively charged ion (cation) and a negatively charged ion (anion).

Compounds formed by ionic bonds. These compounds consist of repeating patterns of cations and anions organized in a crystal lattice. They do not exist as individual molecules.

A weak chemical bond that arises from the attraction between a hydrogen atom covalently linked to a highly electronegative atom (usually oxygen or nitrogen) and another electronegative atom.

Weak attractions between molecules that arise from temporary, fluctuating, uneven distributions of electrons within the molecule.

The process of making and breaking chemical bonds. It involves the rearrangement of atoms and molecules.

The starting molecules involved in a chemical reaction.

The final molecules that result from a chemical reaction.

A state in a reversible chemical reaction where the rates of the forward and reverse reactions are equal. It does not mean the concentrations of reactants and products are the same.

The ability of a molecule to attract or repel electrons, leading to a slightly positive or negative end.

A solution where water is the dissolving agent.

A substance that has an affinity for water, meaning it readily dissolves in water.

A substance that repels water, meaning it does not dissolve in water.

The process of water molecules dissociating into hydrogen ions (H+) and hydroxide ions (OH-) with equal rates.

A measure of the acidity or basicity of a solution.

A substance that increases the hydrogen ion (H+) concentration of a solution, making it more acidic.

A substance that decreases the hydrogen ion (H+) concentration of a solution, making it more basic.

A buffer solution is a mixture of a weak acid and its conjugate base, which resists changes in pH upon addition of small amounts of either acid or base. This is because the weak acid can neutralize added base, and the conjugate base can neutralize added acid.

Carbon is the backbone of life, forming the basis of all organic molecules. It is able to form long chains and rings, allowing for a wide variety of complex structures.

Functional groups are specific arrangements of atoms in organic molecules that contribute to their unique properties. They often determine how molecules react and interact with other molecules.

Hydrocarbons are organic molecules composed solely of carbon and hydrogen atoms. They form the basis of many fuels and are also found in lipids (fats and oils).

The versatility of carbon stems from its ability to form four covalent bonds. This allows it to create long chains, branched structures, and rings, leading to the vast diversity of organic molecules.