Chemistry - Test 4

Democritus

first suggested the existence of the atom and gave it the name "atomos" meaning "can not be cut"

Aristotle

taught that all materials were not made of atoms but of the 4 elements: earth, fire, water, and air

Dalton

believed that atoms were solid spheres created the solid sphere model

Dalton's atomic theory

1. all matter is made of atoms that are indivisible and indestructible

2. all atoms of a given element are identical in mass and properties

3. compounds are formed by a combination of 2 or more different kinds of atoms

4. a chemical reaction is a rearrangement of atoms

Thomson

discovered the electron plum pudding model

electron

negatively charged subatomic particle with a mass of 1/1836 amu that orbits the nucleus

Rutherford

discovered protons via the gold foil experiment and said that atoms are mostly empty space with a positive center and random electrons

proton

positively charged subatomic particle with a mass of 1 amu, found in the nucleus; atomic number is the number of protons

Chadwick

discovered the neutron

neutron

a subatomic particle with no charge, a mass of 1 amu, and found in the nucleus; the mass number is the sum of protons + neutrons

Bohr

solar system atom where electrons traveled in orbits around the nucleus

Schrödinger

electron cloud model of an atom

isotopes

atoms of a same element but different atomic masses due to different number of neutrons

periodic table

arrangement of elements in increasing atomic number with similar properties in same columns; Mendeleev used mass/Moseley used atomic numbers

metal

element that are ductile, malleable, shiny, and good conductors of heat and electricity

ductile

metal property that allows it to be drawn into a wire

malleable

property of metals that allows them to be hammered into a foil

nonmetal

element that tends to be a poor conductor of heat and electricity

metalloid

elements that have properties of metals and nonmetals

period

a horizontal row on the periodic table

group

vertical column on the periodic table whose elements have similar properties

alkali metal

any metal in Group 1 of the periodic table

alkaline earth metal

any metal in Group 2

transition metal

Group B (3-12) elements

halogens

elements from Group 17

noble gases

unreactive gases found in Group 18

lanthanides

elements in the 6th period, located underneath the main body of the periodic table in order to save space

actinides

elements in the 7th period, located underneath the main body of the periodic table in order to save space

representative elements

the Group A elements of the periodic table

electron configuration

shorthand notation of the arrangement of electrons in an atom according to increasing energy

• cirlce (s), figure 8 (p), cloverleaf (d),

Aufbau principle

electrons occupy orbitals of lowest energy first

Pauli Exclusion Principle

an orbital has a maximum of 2 electrons with opposite spins

Hund's Rule

every orbital in a sublevel is singly occupied (with same spin) before any orbital is double occupied

size trends

decrease to the right and increase as you go down the periodic table

ionization energy trends

increase to the right and decrease as you go down the periodic table

electronegativity trends

increase to the right and decrease as you go down the periodic table