Chemical Bonds, Reactions, and Periodic Table Properties

Vocabulary practice flashcards covering core chemical bonding, types of chemical reactions, solubility, atmospheric ozone dynamics, biological macro- and trace elements, and periodic table classifications.

Ionic Bond

A chemical bond formed by the transfer of electrons between atoms, resulting in positively charged cations and negatively charged anions held together by strong electrostatic attraction.

Cation

A positively charged ion formed when a metal atom loses one or more electrons; its electron cloud shrinks inward because the positive nuclear charge exceeds the negative charge (e.g., $Na^+$ with a radius of $95\text{ pm}$ compared to parent $Na$ at $186\text{ pm}$).

Anion

A negatively charged ion formed when an atom gains one or more electrons; monoatomic anions are always larger than their parent atoms (e.g., $Cl^-$ with a radius of $181\text{ pm}$ compared to parent $Cl$ at $99\text{ pm}$).

The Octet Rule (Noble Gas Rule)

The principle stating that reactive representative elements tend to undergo chemical reactions that yield the electron configuration of the nearest noble gas.

Covalent Bond

A chemical bond formed between nonmetal atoms by the sharing of a pair of electrons, concentrating electron density between two nuclei.

Polar Covalent Bond

A covalent bond between atoms with unequal nuclear charges, resulting in an uneven division of charge and partial charges ($\text{δ}^+$ and $\text{δ}^-$).

Electrical Dipole

A property of electrically polar molecules, such as $HF$, where two opposite partial charges ($\text{δ}^+$ and $\text{δ}^-$) exist within the same neutral molecule.

Electronegativity

The relative ability of an element's atoms to draw away the electron density of a covalent bond; fluorine has the highest electronegativity, oxygen is second, and metals have the lowest.

Noncovalent Bonds

Weak molecular interactions with small bond energies compared to covalent bonds, including electrostatic interactions, van der Waals forces, hydrogen bonds, and hydrophobic interactions.

Hydrogen Bond

A noncovalent interaction where hydrogen atoms attached to $-OH$, $-NH$, or $-SH$ groups (donors) interact with free electrons of acceptor atoms such as $O$, $N$, or $S$, with bonding energies of $10-40\text{ kJ}\text{ mol}^{-1}$.

Hydrophobic Interactions

The phenomenon in which nonpolar molecules or nonpolar parts of molecules cluster together in aqueous solutions to decrease their exposure to water.

Stratospheric Ozone Cycle

A series of atmospheric reactions in the stratosphere ($10\text{ to }50\text{ km}$) where $UV$ radiation splits $O_2$ into atomic oxygen ($O$), which forms $O_3$; the ozone then absorbs $UV-B$ radiation and converts $UV$ energy into heat.

Combination Reactions

Chemical reactions in which two or more substances react to produce a single substance (e.g., $S + O_2 \rightarrow SO_2$).

Decomposition Reactions

Chemical reactions in which one single substance breaks down to form two or more products (e.g., $PbCO_3 \rightarrow PbO + CO_2$).

Single Replacement Reactions

Chemical reactions in which one element replaces another element in a compound based on the activity series of metals or nonmetal relative reactivity.

Double Replacement Reactions

Chemical reactions involving the exchange of cations between two compounds to form a precipitate, gas, or slightly ionized compound.

Periodic Law

The principle stating that the chemical and physical properties of elements are periodic functions of their atomic numbers.

Ionization Energy

The energy needed to remove an electron from each atom in one mole of its atoms.

Metalloids

Elements located on the borderline between metals and nonmetals in the periodic table that possess properties that are partly metallic and partly nonmetallic.

Neutralization

The chemical reaction between an acid ($HX$) and a base ($MOH_{(aq)}$) to form a salt ($MX_{(aq)}$) and water ($H_2O$), effectively removing their caustic properties.

Macroelements

Essential biological elements required for life, including $H$, $O$, $C$, and $N$ (accounting for almost 99\text{%} of animal body atoms), $S$, $P$, and key biological ions ($Na^+$, $K^+$, $Mg^{2+}$, $Ca^{2+}$, $Cl^-$).

Trace Elements

Biologically essential elements required by organisms in very small quantities, including metals ($Fe$, $Zn$, $Cu$, $Co$, $Mn$) and non-metals ($I$, $Se$).

Periodic Law

The principle stating that the properties of the elements are a periodic function of their atomic numbers.

Ionization Energy

The energy required to remove an electron from each atom in one mole of its atoms.

Macroelements

Biologically essential elements including $H$, $O$, $C$, and $N$ (accounting for almost $99\%$ of body mass in animals), along with $S$ and $P$.

Trace Elements

Biologically important elements present in very small quantities, including metals ($Fe$, $Zn$, $Cu$, $Co$, $Mn$) and non-metals ($I$, $Se$).

Ionic Bond

A chemical bond formed by the transfer of electrons and the attraction of oppositely charged ions, producing rigid crystals with high melting temperatures.

Cation

A positively charged ion formed when a neutral metal atom loses an electron, causing the electron cloud to shrink so the ion is smaller than its parent atom (e.g., $Na^+$ radius is $95\,pm$ vs $Na$ atom at $186\,pm$).

Anion

A negatively charged ion formed when an atom admits one or more electrons, resulting in an electron cloud larger than its parent atom (e.g., $Cl^-$ radius is $181\,pm$ vs $Cl$ atom at $99\,pm$).

Octet Rule (Noble Gas Rule)

The rule stating that reactive representative elements tend to undergo chemical reactions that give them the electron configuration of the nearest noble gas.

Covalent Bond

A chemical bond characterized by the sharing of a pair of electrons between nonmetal atoms, concentrating electron density between two nuclei.

Polar Covalent Bond

A covalent bond formed between atoms with unequal nuclear charges, resulting in an uneven division of charge and partial charges ($\delta^+$ and $\delta^-$).

Electronegativity

The relative ability of an element's atoms to draw away the electron density of a covalent bond, with Fluorine being the highest and metals the lowest.

Hydrogen Bond

A noncovalent interaction where hydrogen atoms of $-OH$, $-NH$, or $-SH$ groups interact with free electrons of acceptor atoms ($O$, $N$, $S$), with bonding energies of $10 - 40\,kJ\,mol^{-1}$.

Hydrophobic Interactions

The tendency of nonpolar molecules or nonpolar parts of molecules to connect in aqueous solutions to minimize contact with water.

Stratospheric Ozone Cycle

A series of reactions in the stratosphere initiated by $O_2 + \text{UV radiation} \rightarrow 2\,O$ that absorbs harmful UV-B radiation and converts UV energy into heat.

Combination Reactions

Chemical reactions in which two or more substances react to produce a single new substance (e.g., $CaO + H_2O \rightarrow Ca(OH)_2$).

Decomposition Reactions

Chemical reactions in which a single substance breaks down to form two or more simpler substances (e.g., $PbCO_3 \rightarrow PbO + CO_2$).

Single Replacement Reactions

Chemical reactions in which one element replaces another element in a compound according to the activity series (e.g., $Zn + NiCl_2 \rightarrow ZnCl_2 + Ni$).

Double Replacement Reactions

Chemical reactions involving the exchange of cations between two compounds, resulting in the formation of a precipitate, gas, or slightly ionized compound.

Metalloids

Elements located along the borderline between metals and nonmetals in the periodic table that demonstrate properties partly metallic and partly nonmetallic.

Neutralization

The reaction between an acid $HX$ and a base $MOH_{(aq)}$ to form a salt and water ($HX + MOH_{(aq)} \rightarrow MX_{(aq)} + H_2O$), neutralizing their caustic properties.

Periodic Law

The principle stating that the chemical and physical properties of the elements are periodic functions of their atomic numbers.

Ionization Energy

The amount of energy required to remove an electron from each atom in one mole of its atoms.

Metalloids

Borderline elements located between metals and nonmetals in the periodic table that exhibit properties that are partly metallic and partly nonmetallic.

Macroelements

Elements essential for life that constitute the vast majority of biological mass, including $\text{H}$, $\text{O}$, $\text{C}$, and $\text{N}$ (accounting for almost $99\%$ of atoms in animal bodies), along with $\text{S}$ and $\text{P}$.

Trace Elements

Biologically important elements required in very small quantities, including metals such as $\text{Fe}$, $\text{Zn}$, $\text{Cu}$, $\text{Co}$, and $\text{Mn}$, as well as non-metals $\text{I}$ and $\text{Se}$.

Neutralization

A chemical reaction in which the caustic properties of an acid ($\text{HX}$) are neutralized by a base ($\text{MOH}_{(aq)}$) to produce a salt ($\text{MX}_{(aq)}$) and water ($\text{H}_2\text{O}$).

Ionic Bond

A chemical bond formed by the transfer of electrons and the electrostatic attraction between oppositely charged cations and anions.

Cation

A positively charged ion formed when a parent atom loses one or more electrons; the excess nuclear charge pulls the remaining electron cloud inward, making metal cations smaller than their parent atoms (e.g., $\text{Na}^+$ radius is $95\,\text{pm}$ vs. $\text{Na}$ atom radius of $186\,\text{pm}$).

Anion

A negatively charged ion formed when a parent atom gains one or more electrons, expanding the electron cloud and making monoatomic anions larger than their parent atoms (e.g., $\text{Cl}^-$ radius is $181\,\text{pm}$ vs. $\text{Cl}$ atom radius of $99\,\text{pm}$).

Octet Rule (Noble Gas Rule)

The rule stating that reactive representative elements tend to undergo chemical reactions that give them the stable electron configuration of the nearest noble gas.

Covalent Bond

A chemical bond formed between nonmetal atoms through the sharing of an electron pair, concentrating electron density between two nuclei.

Polar Covalent Bond

A covalent bond formed between atoms with unequal nuclear charges, resulting in an uneven division of charge where shared electrons shift toward the more electronegative atom, creating partial charges ($\delta^+$ and $\delta^-$).

Electronegativity

The relative ability of an element's atom in a covalent bond to draw shared electron density toward itself; fluorine has the highest electronegativity, oxygen is second, and metals have the lowest.

Hydrogen Bond

A noncovalent interaction with bond energy between $10\text{--}40\,kJ\,mol^{-1}$ in which a hydrogen donor group ($\text{-OH}$, $\text{-NH}$, or $\text{-SH}$) interacts with free electrons on an acceptor atom ($\text{O}$, $\text{N}$, or $\text{S}$).

Hydrophobic Interactions

Weak molecular interactions in aqueous solutions causing nonpolar molecules or nonpolar molecular regions to aggregate together, reducing their exposed surface area in water.

Stratospheric Ozone Cycle

A cyclic sequence of reactions occurring in the stratosphere ($10\text{ to }50\,\text{km}$) that absorbs incoming high-energy $\text{UV-B}$ radiation and converts it into heat energy.

Combination Reaction

A chemical reaction in which two or more substances react together to form a single product.

Decomposition Reaction

A chemical reaction in which a single substance breaks down to produce two or more simpler substances.

Single Replacement Reaction

A chemical reaction in which one element replaces another element in a compound based on their relative positions in the activity series.

Double Replacement Reaction

A chemical reaction involving the exchange of cations between two ionic compounds to yield a precipitate, a gas, or a slightly ionized compound.