Matter and Atomic Structure Section 3.2- How Atoms Combine Chapter 3 Matter and Atomic Structure Section 3.2- How Atoms Combine

Vocabulary Compound Substance composed of atoms of two or more different elements that are chemically combined. Exp. Water molecule (hydrogen & oxygen) Exp. Table salt (chlorine – poisonous & sodium –toxic)

Vocabulary Chemical bond Force that hold the atoms of elements together in a compound.

COMPOUNDS Most compounds on earth are held together by 2 types of bonds: Covalent bonds Ionic bonds

Vocabulary Covalent bond Two atoms combine with each other by sharing electrons. C=caring=sharing Exp. Water molecule 2 Hydrogen share Electrons with 1 oxygen

Vocabulary Ion An atom that gains or loses and electron is a charge particle. Ionic bond The attractive force between to ions of opposite charge. Example Table salt (NaCl) One of the most common compounds on Earth magnesium oxide (MgO). Compounds formed by ionic bonding are known as ionic compound.

Covalent bond vs. Ionic bond

Ions Atoms gain/loose electron from their outermost energy levels. Anion-When an atom gains an e-, it becomes more negative. Cation-When an atom looses an e-, it becomes less negative and more positive.

Vocabulary Chemical Reaction Change of one or more substances into other substances.

Chemical Reaction Example- Formation of water H2O

Chemical Reaction Example- Formation of Rust Fe2O3

Chemical Reaction Example- Photosynthesis Light energy + carbon dioxide + water = glucose + oxygen Q + 6CO2 + 6H2O = C6H12O6 + 6O2

Mixture A mixture is a combination of two or more components that retain their identity. Homogeneous mixture Components are NOT recognized easily (homo=same) Ex. Coffee Heterogeneous mixture Components are recognized easily (hetero=different) Ex. Soil

Solutions A homogeneous mixture is called a solution. Solid solution-Metal alloys: Bronze; mixture of Copper (Cu) and Tin (Sn) atoms, Brass; mixture of Copper (Cu) and Zinc (Zn) Liquid solution: Magma – molten rock/lava Gaseous solution: Atmosphere/Air

Vocabulary Acid Substance that produces (H+) hydrogen ions in water. Most common in our environment -carbonic acid Responsible for the dissolution of limestone; forming caves.

Vocabulary Base Substance that produces (OH+) hydroxide ions in water. A base can neutralize an acid.