Chem Chap 12 definitions

Electron configuration

Distribution of electrons of an atom into atomic orbitals

Aufbau principle

Order in which the electrons fill up to form the electron configuration

Orbital diagram

Pictorial representation of the location and spin of electrons in an atom

Shell

Grouping of electrons by energy level within an atom

Subshell

Grouping of electrons in a shell according to the shape of their orbitals

Orbital

Three-dimensional space around the nucleus with the maximum probability of finding an electron

Atomic Size

Size of the atom, diameter of the atom

Ionization Energy

Energy required to remove an electron from a gaseous atom

Electronegativity

Relative ability of an atom in a molecule to attract shared electrons to itself

Core Electrons

Electrons in inner energy levels (or shells), not involved in bonding

Valence Electrons

Electrons in the outermost energy level (or shell), involved in bonding

Polar Covalent Bond

Covalent bond with an unequal sharing of electrons

Nonpolar Covalent Bond

Covalent bond with an equal sharing of electrons

Bond Polarity

Bond with a partial (d) positive and partial (d) negative charge

Dipole Moment

Property of a molecule whose charge distribution can be represented by a partial (d) positive and partial (d) negative charge

Octet Rule

All atoms (but H, He) want to have 8 (or 0) valence electrons

Duet Rule

H and He want to have 2 (or 0) valence electrons

Unshared (or Lone Pairs)

Pairs of electrons that are not shared or involved in bonding between two atoms in a Lewis structure

Resonance

When more than one Lewis structure can be drawn for a molecule

Atomic Size Trend

Increases from right to left across a period and from top to bottom down a group.

Ionization Energy Trend

Increases from left to right across a period and down to up in a group.

Electronegativity Trend

Increases from left to right across a period and down to up in a group.

Cations

Positive ions that always have a smaller atomic size than their neutral form.

Anions

Negative ions that always have a larger atomic size than their neutral form.

Steps to Write a Lewis Structure

1. Sum the valence electrons for all atoms. 2. Identify the central atom. 3. Use a line to form a bond. 4. Arrange remaining electrons to satisfy the octet rule.

What’s pressure?

Measure of force gas exerts on surroundings

Barometer and Manometer

Barometer - device used to measure atmospheric pressure

Manometer - device used to measure pressure

h = height (in this case used to measure the air pressure in column)

3 properties of gases

• Variable shape and vol

• Mixes completely with other gases

• Exerts force on surroundings “pressure”

Units of pressure

Atmosphere, mmHg, torr, inHg, Pascal (Pa), psi

1 standard atm is = ___=

1 standard atm = 1.01325 Bar = 760 mmHg = 760 torr = 29.92 in Hg = 101,325 Pascal = 14.69 psi

What’s Boyle’s Law

At constant temperature, pressure and volume are inversely proportional

PV = PV

P = atm

What is Charles Law?

At constant pressure, volume and temperature are proportional (equal)

V/T = V/T

What is avogadro’s law?

At constant temperature and pressure, volume and moles are directly proportional (equal)

V/n(moles)

V in liters

Dalton’s law?

In a mixture of gases, the partial pressure of each gas added together = the total pressure of all gases

P total=P1+P2+P3+...

What is molar gas volume?

1 mole of gas at STP = volume of 22.4 L

Ideal Gas Law Formula

PV = nRT

What is Gas Law Constant

0.0821 L atm or 8.314 kPa L

What is Kinetic Molecular Theory of Gases??

1. Gases consist of tiny particles (atoms/molecules)

2. Particles are so small, compared to distance between them, that the volume (size) of the individual particles are negligible.

3. Particles in constant, random motion, colliding w walls of container = pressure exerted by gas

4. Particles not assumed not to attract or repel one another

5. Avg kinetic energy of gas particles directly proportional to Kelvin temp of gas