Periodic Trends and Bonding

Flashcards about periodic trends, atomic models, and bonding concepts from chemistry lecture notes.

What are the periodic trends discussed?

Ionization energy, electron affinity, atomic radius, electronegativity.

What does Coulomb's Law describe in Chemistry?

Describes the structure and properties of atoms and molecules.

What is the Range of Uncertainty (ROU)?

Range of values as a + or - .

What is Precision?

How reproducible a measurement is (low ROU).

What is Accuracy?

How close a measured value is to a true value.

What happens in Emission/Release Spectrum?

When electricity is run through a gas, it emits light which can be separated using a prism.

What happens in Absorption Spectrum?

When light is run through a gas, the electrons absorb the energy and jump to the excited state, absorbing certain wavelengths.

What are subshells?

Energy levels split into subshells; there are 'n' subshells in the 'nth' energy level.

What are examples of subshells?

S, P, D, F

What are orbitals?

Subshells split into orbitals; there is always an odd number of orbitals.

What is Pauli’s Exclusion Principle?

Electrons occupying the same orbital don't have the same spin.

What is Aufbau Principle?

Electrons always fill into the lower energy orbitals first.

What is Hund’s Rule?

Electrons spread throughout degenerate orbitals before they group together

What is Coulomb’s Law Equation?

F = (kq1q2) / d^2

What is Atomic Radius?

The distance from the nucleus to the valence shell.

How to calculate Effective Nuclear Charge (ENC)?

ENC = #protons - #shielding electrons

What is Ionization Energy?

Energy needed to remove one electron from the atom.

Which atoms have LOW IE because their valence electrons are in a higher energy subshell?

Nitrogen, Boron, and Carbon

Which atoms have LOW IE because they have paired valence electrons that repel each other strongly?

Oxygen, Fluorine, and Neon

What is Electron Affinity?

The amount of energy released when accepting one electron.

Which elements have an EA of 0 or lower?

Noble gases, Alkaline earth metals, and nitrogen.

What is electronegativity?

The strength a bonded electron feels pulling on it by the nucleus of both atoms it's bonded to.

How does the radius affect electron removal?

Removing repulsive force = stronger attraction. Decreases when electrons are removed.

When does the radius increase?

Increases when electrons are added.

What is Ionic Bond?

An ionic bond forms when the two atoms exchange electrons to form ions.

What is Covalent bond?

A covalent bond forms when the two atoms share electrons.

Why do atoms form covalent bonds?

Atoms form as many covalent bonds as they need to fill their valence shell and get a full octet - 8 electrons.

What is Formal Charge?

The charge surrounding ONE atom.

How do you calculate formal charge?

FC = #Valence - #Real Valence

What is VSEPR theory?

Pairs of electrons in the valence shell repel each other which effects their shape.

What is Molecular Geometry?

Takes into account ONLY the bonds that are bonded to an atom.

What is Electron Geometry?

Takes into account the lone pairs AND the bonds.

How are charges distributed in polar covalent bonds?

Electrons spend more time around the more electronegative atom so becomes partially negatively charged therefore the atom with the lower EN becomes partially positively charged.

What are Dipole Moments?

Electromagnetic fields generated by polar bonds. Represented by arrows that show which end is partially negative and which is partially positive.

How is the symmetry of molecules related to polarity?

A polar molecule is asymmetrical while a nonpolar molecule is symmetrical.

What are intermolecular forces?

The forces of attractions between two compounds are referred to as intermolecular forces.

What is Ion-Ion Force?

Strongest IMF, WHOLE charges, high MP/BP, Do not evaporate at room temperature.

What is Dipole - Dipole Force?

Strong, Happens between polar molecules, Not full charges like ion-ion, Lower MP/BP, Evaporate at room temperature.

What are Hydrogen Bonds?

Polar molecules with highly positive hydrogens, H is bonded to N, O, or F, leaving it exposed with no electrons, Weaker than ionic compounds, stronger than dipole-dipole, Higher MP/BP, Usually evaporates at room temperature.

What are London Dispersion Forces?

Attractive forces between any two molecules, Shape of orbitals shift due to environment so there are minor partial charges, They can attract eachother, Very low MP/Bp, Evaporate at room temperature.