Concepts (Mid Term II)

Question 1

Z Effective (Zeff)

Answer 1

The net positive charge pulling e- towards the nucleus. The stronger the pull on the outermost e-, the higher the Zeff.

Question 2

Isoelectric Series

Answer 2

A groups of ions that have the same number of e-

Question 3

Electron Affinity (EA)

Answer 3

The energy released when a gaseous atom gains an e- to form an anion. DeltaE = EA

Inverse of IE

Question 4

Ionization Energy (IE)

Answer 4

The amount of energy required (added) to remove an e- from an isolated atom or molecule (gaseous)
Eel = k(-1)Zeff / d

Inverse of EA

Question 5

Lattice Energy

Answer 5

The amount of energy released when gas-phase ions combine to form a mole of a crystalline solid smaller distance = larger charge
larger distance = smaller charge
Eel = K ((Q+ * Q-)/d)

Question 6

Electronegativity

Answer 6

An atom’s tendency to attract electrons towards itself within a covalent bond

Small radius, a large Zeff = a lot of electronegativity

Question 7

Photoelectric Spectroscopy

Answer 7

an experimental technique that measures the relative energies of electrons in atoms and molecules.

Question 8

Electrostatic potential energy (Eel)

Answer 8

the energy a charged particle has b/c of its position relative to another charged particle
DIRECTLY proportional to the product of the charges of the particle and INVERSLEY proportional to the distance between them

Also called coulumbic attraction

Question 9

Binary Molecular Compounds

Answer 9

Two non mentals

Question 10

Binary Ionic Compounds

Answer 10

Metal and nonmetal

Question 11

Polyatomic Ion

Answer 11

Molecular ions composed of two or more atoms bonded by covalent bonds and acting as a single unit, but unlike molecules, they have a net charge on them

Question 12

Oxoacids

Answer 12

A compound composed of oxoanions bonded to H+ ions

Question 13

Binary Acids

Answer 13

Hydrogen combined with a nonmetal element

Question 14

Allotropes

Answer 14

Different molecular forms of the same element

Question 15

Resonance

Answer 15

A characteristic of e- distribution in which two or more equivalent Lewis structures can be drawn for one compound

Question 16

Electron Pair Delocalization

Answer 16

The spreading out of e- density over several atoms
reduces the e- potential energy and lowers the energy of the molecule –> resonance stabilization

Question 17

Bond Length

Answer 17

the distance between the centers (nuclei) of two covalently bonded atoms

Question 18

Bond Order

Answer 18

The number of bonds between atoms; 1 for a single bond, 2 for a double bond, 3 for a triple bond
For resonance structures, take an average

Question 19

Bond Energy/Bond Strength

Answer 19

the amount of energy needed to break a bond (same number as energy needed to make the bond)

As the bond order increases, the bond strength increases as atoms in bonding come closer to each other while bond length decreases.

Question 20

Formal Charge

Answer 20

The value calculated for an atom in a molecule or polyatomic ion by determining the difference between the number of valence e- in the free atom and the sum of the lone-pair e- plus half the e- in the atom’s bonding pair

Question 21

Free Radical

Answer 21

an atom, ion, or molecule with unpaired valence e-
Generally makes things very reactive

Question 22

Expanded Octets

Answer 22

When atoms may have more than 8 e- associated with them. Only applicable to 3rd row elements

Question 23

Bond Angle

Answer 23

The angle (in degrees) shown by lines joining the centers of two atoms to a third atom to which they are chemically bonded

Question 24

VSEPR

Answer 24

Valence Shell Electron Pair Repulsion Theory
A model predicting the arrangement of valence e- lairs around a central atom that minimizes their mutual repulsion to produce the lowest energy orientation

Based on fundamental chemical principle that e- have neg charges and repel each other

Question 25

Steric Number

Answer 25

The sum of the number of atoms bonded to a central atom plus the number of lone pairs of e- on the central atom

Question 26

Bond Dipole

Answer 26

Separation of electrical charge created when atoms w different electronegativities form a covalent bond
An unequal distribution of e- between two atoms produces a partial neg charge on one end of the bon and a partial positive charge on the other

Question 27

Permanent Dipole

Answer 27

Permanent separation of electrical charge in a molecule resulting from unequal distributions of bonding and/or lone pairs of e-

Question 28

Dipole Moment

Answer 28

a measure of the degree to which a molecule aligns itself in an applied electric field, a quantitative expression of the polarity of a molecule

Question 29

Valence Bond Theory

Answer 29

A quantum mechanics-based theory of bonding that assumes covalent bonds from when half-filled orbitals on different atoms overall or occupy the same region in space

A chemical bond forms when the atomic orbitals of two atoms overlap

Question 30

Sigma Bond

Answer 30

A covalent bond in which the highest e- density is between the two atoms along the internuclear axis

Single bonds

Question 31

Pi Bond

Answer 31

A covalent bond in which e- density is greatest above and below the internuclear axis

double bond

Question 32

Hybridization

Answer 32

In valence bond theory, the mixing of atomic orbitals to generate new sets of orbitals that may form sigma bonds with other atoms

Question 33

Hybrid Atomic Orbital

Answer 33

In valence bond theory, one set of equivalent orbitals about an atom created when specific atomic orbitals are mixed