Types of Bonds

Front

Valence Electron Noun

---

[vay-lence i-lek-tron]

Back

Valence Electron

---

An electron in the outermost shell of an atom that can be involved in forming chemical bonds with other atoms.

---

Example: This diagram of a sodium atom shows electrons in shells. The single electron in the outermost shell is the valence electron.

Front

Octet Rule Noun

---

[ok-tet rool]

Back

Octet Rule

---

The principle that main-group atoms tend to bond in such a way that they each have eight electrons in their valence shell.

---

Example: An oxygen atom with six outer electrons bonds with two hydrogen atoms, sharing electrons to complete its outer shell with eight, following the octet rule.

Front

Ionic Bond Noun

---

[ay-on-ik bond]

Back

Ionic Bond

---

A chemical bond formed through electrostatic attraction between two oppositely charged ions, typically a metal and a non-metal.

---

Example: Positively charged sodium ions (Na+) and negatively charged chloride ions (Cl-) attract each other, forming a repeating, grid-like structure called a crystal lattice.

Front

Covalent Bond Noun

---

[koh-vey-luhnt bond]

Back

Covalent Bond

---

A chemical bond that involves the sharing of electron pairs between atoms, typically occurring between two non-metal atoms.

---

Example: This image shows a model of a carbon dioxide (CO₂) molecule, where lines connecting the atoms represent the covalent bonds holding them together.

Front

Metallic Bond Noun

---

[muh-tal-ik bond]

Back

Metallic Bond

---

A type of chemical bond formed between positively charged metal ions and the delocalized electrons shared among them.

---

Example: This diagram shows how metal atoms form a strong bond. Positive metal ions are arranged in a fixed pattern, held together by freely moving electrons.

Front

Ion Noun

---

[ay-on]

Back

Ion

---

An atom or molecule that has a net electrical charge due to the loss or gain of one or more electrons.

---

Example: This diagram shows an atom with four positive protons in the nucleus but only three negative electrons in orbit, resulting in a net positive charge.

Front

Cation Noun

---

[kat-ay-on]

Back

Cation

---

A positively charged ion formed when a neutral atom loses one or more electrons, typically a characteristic of metal atoms.

---

Example: This image shows a neutral sodium atom losing an electron to become a sodium cation (Na+), resulting in a positive charge because it has more protons than electrons.

Front

Anion Noun

---

[an-ay-on]

Back

Anion

---

A negatively charged ion formed when a neutral atom gains one or more electrons, typically a characteristic of non-metal atoms.

---

Example: A neutral chlorine atom (17 protons, 17 electrons) gains an electron, becoming a chloride anion (Cl-) with a negative charge (17 protons, 18 electrons).

Front

Crystal Lattice Noun

---

[kris-tl lat-is]

Back

Crystal Lattice

---

The symmetrical three-dimensional arrangement of atoms, ions, or molecules in a crystalline solid, such as in an ionic compound.

---

Example: This diagram shows a crystal lattice, the repeating three-dimensional pattern of ions in a crystal, using table salt (NaCl) as an example.

Front

Formula Unit Noun

---

[fawr-myuh-luh yoo-nit]

Back

Formula Unit

---

The simplest whole-number ratio of cations and anions that represents the electrically neutral composition of an ionic compound.

---

Example: This image shows how to find the formula unit for sodium phosphide by balancing the charges of its ions, resulting in the formula Na₃P.