General Chemistry I

Ch

Nano (n)

10^-9

Micro (µ)

10^-6

Milli (m)

10^-3

Centi (c)

10^-2

Deci (d)

10^-1

Deka (dk)

10¹

Hecto (h)

10²

Kilo (k)

10³

Mega (M)

10⁶

Giga (G)

10⁹

Period and Groups

This is the horizontal aspect of the periodic table. Ranging from left to right.

This is the vertical aspect of the period table. Top to bottom.

What are the exceptions to the electron configuration model?

• Chromium (Cr)

• Molibdenum (Mo)

• Copper (Cu)

• Silver (Ag)

• Gold (Au)

Electronegativity

Definition: This describes an atoms pull on another shared atom. The greater this is the stronger the pull.

Trend:

• Increase as you move across a period (left → right)

• Decrease as you move across a group (top → bottom)

As you move right of the group, this increases because the number of proton increases allowing more effective electron pull. But as you move down the period, this decreases because the protons get shielded by outer shell electron, making the electron pull less effective.

Exception: Noble Gases

Atomic Size

• Decrease as you move across a period (left → right)

• Increases are you move across a group (top → bottom)

Consider as you move across a period, the protons increase generating stronger pull towards the electron. As you move across a group, although proton increases, the orbital shells also increase, increasing the atomic size

Ionic Size

• All Cation Ions have a smaller ionic size compared to its parent atom

• All Anion Ions have a greater ionic size compared to its parent atom

Since Cations lose electron, and Anions gain electron, Anions will occupy for electron shells thereby increasing ionic size.

Ionization Energy

Definition: The energy required to remove electrons from an atom/ion

Trend:

• Increases as you move across the period (left → right)

• Decrease as you move across the group (top → bottom)

As you move across the period, the amount of proton increases but the electrons stay on the same electron shell. Therefore there are more pull from the proton to the electron. Increasing the required energy. But as your move across the group, more electron occupy the further electron shell decreasing energy requirement.

Exception:

Group 2 > Group 13

Group 15 > Group 16

By the trend group 13 and group 16 should require more ionization energy than compared to group 2 and group 15 respectively. But because of the electron configuration, it is much easier to pull lone pairs than it is to pull paired electrons. Since Group 2 and Group 15 atoms have more paired electron, those group have greater ionization than Group 13 and 16.

Electron Affinity

Definition: This describes the heat released when an atom/ion gains electron

Trend:

• Increases as you move across the period (left → right)

• Decreases as you move across the group (top → bottom)

As you move across the period the nuclear charge of the atom increases, making the atom more energetic to electrons. But as you move down the group the atomic radius increases decreasing proton attraction, and there is more electron shielding from the inner electrons.

Angular Node

This described the regions on the atomic orbitals that will not contain any electrons.

Determined by the Quantum Number L

Radial Node

This describes the region in the atomic orbital that will not contain any electrons.

Determined by the Quantum number n - L - 1

Electron Geometry:

2 Electron Group

Structure: Linear

Angle: 180

Electron Geometry:

3 Electron Group

Structure: Trigonal Planar

Angle: 120

Electron Geometry:

4 Electron Group

Structure: Tetrahedral

Angle: 109.5

Electron Geometry:

5 Electron Group

Structure: Trigonal Bipyramidal

Angle: (90, 120)

Electron Geometry:

6 Electron Group

Structure: Octahedral

Angle: 90

Molecular Geometry:

2 Electron Group

0 Lone Pair: Linear (180)

Molecular Geometry:

3 Electron Group

0 Lone Pair: Trigonal Planar (120)

1 Lone Pair: Bent

Molecular Geometry:

4 Electron Group

0 Lone Pair: Tetrahedral (109.5)

1 Lone Pair: Trigonal Pyramidal

2 Lone Pair: Bent

Molecular Geometry:

5 Electron Group

0 Lone Pair: Trigonal Bipyramidal (90, 120)

1 Lone Pair: Seesaw

2 Lone Pair: T-Shaped

3 Lone Pair: Linear

Molecular Geometry:

6 Electron Group

0 Lone Pair: Octahedral (90)

1 Lone Pair: Square Pyramidal

2 Lone Pair: Square Planar

3 Lone Pair: T-Shaped

4 Lone Pair: Linear

Formula:

Bond Order for Molecular Orbital Diagram

Bond Order = (Bond Electron - Antibonding Electron) / 2

Avogadro’s Number

6.022 × 10²³

Arrhenius Acid

A substance that reacts in water to produce hydronium (H₃O⁺) ion

Arrhenius Base

A substance that reacts in water to produce hydroxide (OH^-) ion

Equation for Heat Energy

q = heat (J)

m = mass (g)

s = specific heat capacity

t = temperature (C)

Speed of Light

c = 3.00 × 10⁸ (m/s)

Equation for Speed of Light

c = 3.00 × 10⁸ (m/s) (Speed of Light)

ν = frequency (s^-1)

λ = wavelength (m)

Equation for Energy of  A Photon

E = Energy of Photon (J)

h = 6.626 × 10^-34 (J * s) (Planck’s Constant)

v = frequency (s^-1)

Rydberg’s Constant for Hydrogen

R_h = 1.09678 × 10⁷ (m^-1)

Rydberg’s Constant for Energy

R_y = 2.18 × 10^-18 (J)

Equation for Rydberg’s Wavelength

λ = wavelength (m)

R_h = 1.09678 × 10⁷ (m^-1) Rydberg’s Constant for Hydrogen

De Broglie’s Matter Wave Equation

λ = wavelength (m)

h = 6.626 × 10^-34 (J * s) (Planck’s Constant)

m = mass (g)

v = speed (m/s)

Rules for Assigning Oxidation Number

1. Oxidation number must add up to the total charge of the molecule, formula unit, or ion

2. All atoms of the free elements have an oxidation number of 0

3. Metals in 1A, 2A, and Al have an oxidation number of +1, +2, and +3, respectively

4. H and F in a compound have an oxidation number of +1 and -1, respectively

5. Oxygen has an oxidation number of -2

6. Group 7A has an oxidation number of -1

7. Group 6A has an oxidation number of -2

8. Group 5A has an oxidation number of -3

Specific Heat Capacity of Water

4.18 J/g C