ATOMS, ELEMENTS COMPOUNDS AND MIXTURES 7-5.1 & 7-5.2

ATOMS Matter is composed of extremely small particles, too small to be seen with a classroom microscope, called atoms. Atoms: smallest part of an element that has the chemical properties of the element. A single atom has mass and takes up space.

PARTS OF AN ATOM Electron: Proton: Neutron: smallest part of an atom Charge: negative Orbits around the atom (like moon around planet) Proton: Postive charge In the nucleus of the atom # of protons defines the atom Neutron: No charge because they are neutral Nucleus of atom: made of neutrons and protons

Electron Location Innermost ring holds 2 electrons 2nd ring can hold up to 8 3rd ring can hold up to 18 4th ring can hold up to 32 The more COMPLETE the outermost ring is, the more “stable” the atom will be.

MODEL OF ATOM Watch Brain Pop

ELEMENTS Elements: pure substances that cannot be changed into simpler substances. Elements are composed of one kind of atom. Ex: Gold, Oxygen, Silver, Helium, Hydrogen All elements found on periodic table

COMPOUNDS Pure substances that are composed of two or more types of elements that are chemically combined. Compounds can only be changed into simpler substances called elements by chemical changes. One way that two or more atoms can combine is to form a molecule. Ex: H2O, CO2, C6H12O6

MIXTURES Composed of two or more different substances that retain their own individual properties Combined by physical means Can be separated by physical means (filtration, sifting, or evaporation). Mixture may be heterogeneous or homogeneous.

TYPES OF MIXTURES heterogeneous mixture Not uniform (same) throughout Substances can be visibly distinguished Ex: Salad, bag of sand and rocks homogeneous mixture Uniform throughout Substances can not be visibly distinguished Another name = solution Ex: Salt water and kool aid **Brain pop

MATTER