FTCE - Science K-6 (Physical and Chemical Properties and Changes(

Matter

anything that has mass and takes up space

atoms

the smallest units of an element that display the characteristic properties of that element.

Protons, neutrons, electrons

• Protons are positive and in the nucleus

• Neutrons are neutral and in the nucleus

• Electrons are negative and in the cloud

ground state

the electrons in the atom are arranged so the atom has its lowest possible energy.

The number of protons in the nucleus characterizes

the type of atom

Molecules

electrically neutral particles made of two or more atoms joined together by a molecular bond

chemical reaction

rearranges the atomic bonds between atoms, to form a new substance.

ionic bond

electrons are removed from one atom and given to an atom of another element

The two particles have opposite charges and attract each other by the electromagnetic force, which bonds the two particles together.

(taking)

molecular bond

electrons are shared between atoms, covalent bonds

(Sharing)

Compounds

groups of two or more different elements held together by molecular bonds.

pure substance

consists of only one type of atom or molecule

element

only one type of atom present

compound

each molecule has more than one type of atom chemically combined.

mixture

the atoms, molecules, or particles of two or more different materials are mixed together but are not chemically combined

homogeneous mixture

uniform throughout the mixture, any sample of the mixture will have the same ratio of parts

heterogeneous mixture

not uniformly mixed

Solutions

homogeneous mixtures in which one substance dissolves in another.

solute

The solute is the material that is dissolved in the solvent.

In a solution, you put the solute into the solvent.

Melting

Solid to a liquid (gaining energy)

Vaporization (boiling)

liquid to gas (gaining energy)

Sublimation

solid straight to a gas (gaining energy)

Condensation

gas to a liquid (losing energy)

Freezing

liquid to a solid (losing energy)

Deposition

gas straight to a solid (losing energy)

melting point.

When a solid is heated, the temperature of the solid rises until it reaches its melting point. Any additional energy contributes to the melting. Once all of the solid is melted, the temperature begins to rise again.

boiling point,

Once the liquid reaches its boiling point, the temperature remains steady until all of the matter evaporates and reaches the gas state.

Chemical Reaction Examples

photosynthesis, the digestion of food, frying an egg, and baking bread.

signs of chemical change

gas production (bubbles), light production (fire), a resulting change in temperature, an unexpected color change, rust, and/or the production of a precipitate (formation of a solid from two solutions)