Unit 4: The Periodic Table

periodic law

Chemical properties of the elements are periodic (repeating) functions of their atomic numbers.
What it means: Elements are arranged in order of increasing atomic number across periods so that elements with similar chemical properties fall in the same group.

period

horizontal row of elements in the periodic table

group

vertical column of elements in the periodic table

metals

a class of elements with physical properties that include luster, malleability, ductility, and conductivity
left side of P.T.

metalloids

an element that has properties of both metals and nonmetals
*on the staircase: B, Si, Ge, As, Sb, Te

nonmetals

elements that are usually dull in appearance, brittle, and poor conductors of heat and electricity
right side of P.T.

ductile

can be shaped into a wire
property of metals

luster

shiny
property of metals

electronegativity (E.N.)

an atom's ability to ATTRACT e-'s from another atom during bonding
on a scale of 0 (lowest) to 4 (highest)
Table S

ionization energy (I.E.)

the energy it takes to REMOVE an e- from an atom
Table S

atomic radius

the size of an atom
Table S

ionic radius

the size of an atom after it has lost or gained e-'s to form an ion
+ ions are smaller than their atoms
- ions are larger than their atoms

transition metals

Groups 3-12
form colored solutions

halogen

an element in group 17 of the periodic table

noble gas

an element in group 18 of the periodic table
not reactive (already have an octet)

octet rule

atoms react by gaining or losing electrons so as to acquire the stable electron structure of a noble gas, usually 8 valence electrons

diatomic elements

elements that exist as two atoms bonded (connected) together
Br₂, I₂, N₂, Cl₂, H₂, O₂, F₂ (BrINClHOF)
or
"7H Club"

monatomic elements

elements made of single atoms not connected to each other

metallic character

describes how many metal-like properties an element displays
greatest in lower left corner of P.T.

allotrope

an element that exists in two or more forms that possess different chemical and structural properties

ion

a charged particle

cation

a positively charged ion (lost electrons)

anion

a negatively charged ion (gained electrons)

malleability

the ability of a substance to be hammered or beaten into thin sheets

alkali metals

Group 1, 1 electron in outer level, very reactive, soft, silver, shiny, low density; Lithium, Sodium, Potassium, Rubidium, Cesium, Francium

electron

negatively charged subatomic particle

ductility

the ability of a substance to be drawn, pulled, or extruded through a small opening to produce a wire

alkaline earth metals

group 2, 2 electrons in outer level, includes the metallic beryllium, magnesium, calcium, strontium, barium and radium.

proton

positively charged subatomic particle

conductivity

the ability of a material to allow either heat or electricity to flow through it

neutron

neutral subatomic particle

compound

a substance formed by chemical union of two or more elements in definite proportions

brittleness

The tendency of a solid to crack or break when forces are applied

dull

not shiny (no luster)

valence electron

electrons in the outermost energy level

non-conductor

does not conduct heat or electricity

reactivity

ability of an element to form a bond with another

lewis dot diagram

Diagram of an atom, ion or molecule in which each dot represents a valence electron