Elements and periodic table

•Anything that has mass and takes up space.

• Definite shape• Definite volume

• No definite shape • No definite volume

• No definite shape • Definite volume

•Simplest pure substances•Elements are made up of atoms

•Hydrogen•Oxygen•Calcium

• Pure substances made up of more than one element.

• Atoms of the elements in a compound are chemicallybonded together to form molecules.

•Molecules are changed during chemical reactions.

• Consists of two or more substances mixed together but notchemically combined.• Substances in mixtures can be separated by physical means.

Types of mixtures:• Heterogeneous: not identical throughout •Homogeneous: identical properties throughout

•Dmitri Medeleev- father of the periodic table of elements.

•Groups- are families of elements with similar physical or chemical properties that occupy the same column. There are 18 groups within the periodic table.

•Periods- are horizontal rows of elements whose properties changegradually are predictably. There are 7 periods within the periodic table.

•An element is identified by its chemical symbol.

•The number above the symbol is the atomic number.

•The number below the symbol is the rounded atomic weight of the element.

Properties of elements•Metals- elements that is a good conductor of electricityand heat, usually is shinny, deductive, and malleable.•Metalloids- elements that shares properties with metals and nonmetals.•Nonmetals- elements that are poor conductors of heat and electricity.they can be a gas or a brittle solid at room temperature.

• Atomic number = Protons Electrons• neutrons = rounded• Atomic mass – atomic number

SymbolAtomic Mass

Atomic Number

Charge (if ion)

NaSodiumSodium

23

11

Protons: 11Neutrons: 12Electrons: 11