Atomic Structures & Properties

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Chemcial/ionic bonding

par Yun Shan

Chemistry - Grade 12 Concept Map

par Zane Saghir

Structural, Strength and Stability

par Serena Bravo

Atomic Structure

par Peter Clark

Atomic Structures & Properties

Square Pyramidal

Example: BrF5

Seesaw

Example: SF4

Bond Angles: <90°, <120°

Octahedral

Example: SF6

Bonded Atoms: 6

Trigonal Bipyramidal

Example: PCl5

Bond Angles: 90°, 120°

Bonded Atoms: 5

Tetrahedral

Example: CH4

Bond Angles: 109.5°

Linear

Example: CO2

Bond Angles: 180°

Electron Groups: 2

Aufbau Principle

Niels Bohr, Bohr Model of The Atom (1913)

Contributions - Introduced quantized electron orbits - Explained stability of electron orbits and spectral lines

Inferences: - Electrons Orbit the nucleus - Electrons emit or absorb energy

Observations: - emission spectra of hydrogen show discrete lines

Polarity

The physical properties of solids and liquids depend on intermolecular forces (dispersion, dipole-dipole, hydrogen bonding, ion-dipole) and intramolecular forces (covalent, ionic, metallic). Stronger forces lead to higher melting and boiling points. Covalent network solids are very hard, ionic compounds are hard and brittle, and metals are malleable and conductive. Solubility follows "like dissolves like."

Square Planar

Example: XeF4

Bond Angles: 90°

Bonded Atoms: 4

Electron Groups: 6

T-Shaped

Example: ClF3

Bond Angles: <90°

Lone Pairs: 2

Electron Groups: 5

Trigonal Pyramidal

Example: NH3

Bond Angles: <109.5°

Electron Groups: 4

Trigonal Planar

Example: BF3

Bond Angles: 120°

Lone Pairs: 0

Bonded Atoms: 3

Bent

Example: SO2

Bond Angles: <120°

Lone Pairs: 1

Bonded Atoms: 2

Electron Groups: 3

Hunds Rule

Ernest Rutherford, Gold Foil Experiment (1911)

Contributions - Introduced the nuclear model with a central nucleus - Suggested that electrons orbit the nucleus

Inferences: - Atoms are mostly empty space - The existence of a positively charged nucleus

Observations: - Most alpha particles passed through foil -A few alpha particles were deflected at large angles