Review of Periodic Table

Arrangement

• Arranged in ascending order of electrons

• Periodic Table is arranged by groups + periods.

Groups

• vertical columns

• 18 groups in total

• elements the same group = very similar properties

• elements in a group have same number of valence electrons (electrons in outer shell)

Periods

• horizontal rows

• 7 periods total

• elements in the same period have the same number of shells

Properties

Metals

• make up majority of elements

• most are solid at room temp.

• lustrous (shiny)

• malleable (can make thin sheets)

• ductile (can make wires)

• good conductors of heat/electricity

• high melting/boiling points

Non Metals

• dull

• brittle

• low melting/boiling points

• liquid or gas at room temp

• poor conductors of heat/electricity

Metalloids

• Located on boundary of metals + non metals (staircase)

• 7 metalloids (boron, silicon, antimony, germanium, tellurium, arsenic, polonium)

• Look like metals but have non metal properties

• semi conductors to heat/electricity

Review of Atomic Structure

Components

• made up of 3 subatomic particles

  • electrons

  • protons

  • neutrons

• building block of all matter

• comprise of a nucleus and shells

Protons

• number of protons = number of electrons = atomic number

• atomic mass = 1

• located in the nucleus

• have a positive charge

Neutrons

• number of neutrons = atomic mass - number of protons

• atomic mass = 1

• located in the nucleus

• have not charge

Electrons

• number of electrons = number of protons = atomic number

• atomic mass = 1/1836, practically zero

• located in the shells

• have a negative charge

Nucleus

• comprised of protons and neutrons

• have a positive charge

• contain all the mass of the atom

Shells

• maximum 7 shells to hold electrons

• each period has an increasing number of periods

• negatively charged

• max electrons in shell number equation = 2n², where n equals number of periods/shells

• E.g.. fifth shell can hold a maximum of 2(5)² = 50 maximum electrons

Atomic Mass Units (AMU)

• protons + neutrons = AMU

• electrons hold no weight

Bohr Model

• a way of depicting the atomic structure

• described electrons as ‘orbiting’ the nucleus - as planets orbit the sun

• shows that electrons are in a fixed structure of shells

• depicts that electrons in higher shells have more energy

Schrodinger Atomic Model

• developed ther quantum mechanical model which led to the idea of the electron colud

• introducedthe idea that electrons DO NOT orbit the nucleus