SCH4U1 Unit 1 Review

Developed a series of mathematical equations to describe the motion of electrons in atoms.

Had the idea that electrons have wave properties. Suggested that an electron bound to a nucleus in an atom resembled a standing wave.

Created Heisenberg’s Uncertainty Principle

The ability of some atoms to form a permanent magnet (keeping their electron spins in the same direction even after an electric field is removed).

The weak attraction of a substance to a magnetic source. This term usually applies to individual atoms.

Electrons must be spread out amongst orbitals in such a way that as many electrons as possible remain unpaired.

No two electrons in the same atom can have the same quantum numbers. This leads to the fact that orbitals can hold a max of 2 electrons.

Each electron added will occupy the lowest available energy level.

It is impossible to know the exact location and momentum/speed of an electron at a given moment.

Determines the allowed energies an electron can have, and only shows where electrons are likely to be.

A mathematical description of an orbital, describing where an electron of a given energy is likely to be found.

A plot indicating regions around the nucleus where electrons are likely to be found.

Difference between orbits and orbitals?

Having the same number of electrons per atom, ion, or molecule.

tetrahedral (109.5), trigonal pyramidal (107), bent (104.5)

trigonal bipyramidal (120, 90), seesaw (180, 120, 90), t-shaped (180, 90), linear (180)

Octahedral (90), square pyramidal (90), square planar (90), t-shaped (180, 90), linear (180)

Trigonal planar (120), bent (120), NA

Impossible to calculate exact repulsions between electrons

Valence Shell Electron-Pair Repulsion Theory

Number of central atoms

Number of bonding electrons on central atom

Number of lone pairs on central atom

How strongly an atom attracts a pair of bonding electrons when in a covalent bond

Effective nuclear charge. Attraction of the nucleus to a valence electron of interest.

Electron shielding. The blocking of ENC due to inner-shell electrons.

Half-filled atomic orbitals overlap to form a new orbital with a pair of opposite-spin electrons.

An orbital created from the combination of at least 2 different orbitals

The process of forming hybrid orbitals from at least 2 different orbitals

• Crystal lattice structure

• Alternating (+) and (-) charges

• Hard & brittle

• High MP

• Conducts electricity in solution

• Electrostatic interactions

• Electron sea theory

• Hard

• Sheen

• Malleability

• High MP/BP

• Electrical conductivity

• Low IE

• Individual molecules held together by intermolecular forces

• IMFs determine structure and properties

• Intramolecular forces = woven network

• Extreme hardness

• High MP/BP

• Diamond, graphite, buckyball/fullerene, carbon nanotube

Interlocking tetrahedral structure

• Hexagonal sheet

• Slippery & black

• Electrical conductor

• Soccer-ball like structure

• Structure similar to buckyballs

• Cylindrical

Covalent network crystal, conducts electricity a little at room temperature, increases conductivity with temperature

• Si, Ge

Modifying semiconductors to make them have specific conductive properties

Interactions between opposite electric charges.