Chemistry quiz 1 unit 1

knowledge that comes from investigation and observation. Ex. planets orbit the sun.

knowledge that explains scientific observations. Ex. model of atom.

International Union of Pure and Applied Chemistry.

IUPAC sets rules and standards for chemists worldwide.

First - all matter is composed of a combination of the 4 elements ; earth, fire, water, and air. Then - all matter is made up of atoms.

(1808) - Dalton discovered matter consists of tiny, indivisible particles called atoms. -Atoms of different elements are different -First model of atom

(1897) -infers there are particles within atoms -created the plum pudding model -discovered electrons

(1911) -discovered protons -conducted the gold foil experiment

(1932) -discovered neutrons

-came up with a model that explained why the electrons did not collapse into the positive nucleus. -He suggested that different atoms have specific energy levels

The unique number of protons in one atom of an element.

The sum of the protons and neutrons in the nucleus of an atom.

Mass number - atomic number = number of neutrons

• a very small unit of mass defined as 1/12 the mass of a carbon -12 atom. 1u = 1.6605402 x 10*-27kg

An electron arrangement where the valence shell is filled with 8 valence electrons.

A generalization stating that when atoms combine, they tend to achieve 8 valence electrons.

A charged entity formed when an atom gains or loses 1 or more electrons.

A positively charged ion.

A negatively charged ion.

The property of having more then 1 possible valance.

An ion made up of more then 1 atom, that acts as a single entity.

Sodium ions (Na) help with nerve impulse transmission and water balance. Others..K/Fe/Ca

A form of an element in which the atoms have the same number of protons as all other forms of that element, but a different number of neutrons. Different mass.

The percentage of a given isotope in a sample of an element. C –> most C -12, a bit C - 14 Cl –> roughly half Cl - 35, half Cl - 36