Arrangement of Electrons and Types of Chemical Bonds

Vocabulary flashcards covering electron arrangements, valence shells, octet rule, chemical bond types, formulas, and chemical reactions from lecture notes.

Electron Shells

Models constructed to represent the energy levels where constantly moving electrons are located around an atom; for atoms up through atomic number $20$, two electrons fill the first shell and eight electrons fill each additional shell.

Valence Shell

The outermost electron shell of an atom.

Octet Rule

The principle stating that if an atom has more than two shells, the outer shell is most stable with eight electrons, causing atoms to give up, accept, or share electrons to achieve eight.

Molecule

A group of atoms bonded together, such as $\text{O}_2$, $\text{H}_2\text{O}$, $\text{C}_6\text{H}_{12}\text{O}_6$, or $\text{N}_2$.

Compound

A molecule containing atoms of more than one element, such as $\text{H}_2\text{O}$ or $\text{C}_6\text{H}_{12}\text{O}_6$.

Ionic Bonding

Chemical bonding formed when two atoms are held together by the attraction between opposite charges.

Ion

A charged atom formed when an atom gains or loses electrons, such as sodium having one more proton than electrons or chlorine having one more electron than protons.

Covalent Bonding

Chemical bonding formed when two atoms share electrons to complete their outer valence shell.

Structural Formula

A chemical formula format that uses straight lines, such as $\text{H}-\text{H}$, where one line indicates one pair of shared electrons.

Molecular Formula

A chemical formula format that simply shows the number of atoms involved, such as $\text{H}_2$.

Double Covalent Bond

A covalent bond in which two atoms share four electrons, creating a bond that is stronger than a single bond, as seen in oxygen gas ($\text{O}_2$).

Shapes of Covalently Bonded Molecules

Representations of molecular geometry including electron models showing covalent bonds, structural models, ball-and-stick models, and space-filling models.

Reactants

Molecules that participate in chemical reactions, shown to the left of the arrow in a chemical equation.

Products

Molecules formed by chemical reactions, shown to the right of the arrow in a chemical equation.

Balanced Chemical Equation

A chemical equation in which the exact same number of each type of atom occurs on both sides of the reaction arrow.