Chapter 2: Dissecting Atoms: Atomic Structure and Bonding

Noble gases

Noble gases

________: the only atoms that have their outermost shells filled with electrons; unreactive.

Sodium

________ becomes a cation as it lost 1 electron, and chlorine becomes an anion because it gained 1 electron.

Heisenberg

________ uncertainty principle: the uncertainty in knowing the locations of electrons at a given moment.

Sp

________ hybridized orbitals: 2 hybridized orbitals, which are the s orbital and one of the p orbitals, and the other two remaining p orbitals remain unchanged; for atoms with 2 bonds; 180° bond angle.

VSEPR theory

________: stands for valence shell electron pair repulsion; predicts the approximate geometry of bonds around an atom.

Ionic bond

________: when the electronegativity difference is very large; greater than 2.

Octet rule

________: the desire of atoms to have filled electron shells.

Electrons

________ are equally shared between the 2 atoms.

Polar covalent bond

________: if the electronegativity difference is smaller; between 0 and 2.

covalent bond

Purely ________: if the electronegativity difference is 0.

Pz

________: an orbital that points in the z direction.

Anion

________: an atom with more electrons than the number of protons in its nucleus.

Aufbau chart

The ________ is helpful for remembering which orbitals to fill first.

Orbital

________: status the actual location in space of where the electron resides.

Sp3

________ hybridized orbitals: 4 hybridized orbitals, which are the s orbital and three p orbitals; for atoms with 4 bonds; 109.5° bond angle.

Ion

________: an atom that has more or fewer electrons than the amount of protons.

hydrogen atoms

Because both ________ need 1 electron to fill its shell, they share their electrons equally (instead of grabbing an electron from each other)

Py

________: an orbital that points in the y direction.

Electronegativity

________: tendency of an atom to attract electrons towards itself.

Px

________: an orbital that points in the x direction.

Cation

________: an atom with fewer electrons than the number of protons in its nucleus.

BeH2

For ________, the beryllium (Be) has two substituents (two identical H atoms), so its sp hybridized.

Attraction

________ between sodium cation and chlorine anion in sodium chlorine is an ionic bond.

Chlorine

________ is an atom in the second- to- last column of the periodic table and has 7 valence electrons.

Carbon

________ (C), hydrogen (H), oxygen (O), and nitrogen (N) are the most prominent elements in organic compounds.

Pi

________ (π): bonds where orbital overlap occurs above and below the nuclei, and not directly between them.

Problem solving

________: Predicting bond dipole moments.

negative charge

Because electrons spend most of the time around chlorine, chlorine gets a partially ________.

positive charge

Because electrons spend less time around hydrogen, hydrogen gets a partially ________.

Dipole moment

________: separation of charge in the bond because the more electronegative atom "bullies "most of the bonding electrons away from the less electronegative atom.

net dipole moment

The ________ is zero because the oxygens are pulling in equal and opposite directions; therefore, they cancel each other out.

Sigma

________ (σ): bonds in which orbital overlap occurs between the two bonding nuclei.

Orbitals

________: electron shells are further subdivided into these; they are the actual location in which an electron can be found.

Hunds rule

________: the electrons should go into different orbitals with the same spin, instead of pairing up into a single orbital with the opposite spin.

lowest energy

First Shell: closest to the nucleus of the atom, has the ________, and can hold up to 2 electrons.

Shell

________: indicates the energy level of a certain electron; a full shell will be spherical in shape.

Dipole vector

________: a distinct arrow that is used to show the direction of the dipole moment, or separation of charge.

Inorganic compounds

________: non- carbon- containing compounds.

lone pairs

Because electrons repel each other, bonds and ________ (non- bonding electron pairs) around an atom want to be as far away from each other as possible.

Electrons

________ are shared, but not equally between the atoms.

Orbital

________: Apartment where the electron resides.

Ionic bonds

________ are usually found in inorganic compounds.

Covalent bonds

________ are found in organic compounds.

Sodium

________ is an atom in the first column of the periodic table and has 1 valence electron.

hydrogen atom

A(n) ________ has 1 electron, so it needs another 1 to fill its shell.

Electrons

________ in atoms are under house arrest.

Electrons

________ repel each other and want to be as far away from each other as possible.

Electrons

________: they are located in the shells surrounding the nucleus, not in the nucleus itself.

Electron House Arrest

Shells and Orbitals

Protons

number of protons cannot be changed without changing the identity of the atom itself; if the number of protons change, it becomes a different element

Ion

an atom that has more or fewer electrons than the amount of protons

Anion

an atom with more electrons than the number of protons in its nucleus

Cation

an atom with fewer electrons than the number of protons in its nucleus

Electrons

they are located in the shells surrounding the nucleus, not in the nucleus itself

First Shell

closest to the nucleus of the atom, has the lowest energy, and can hold up to 2 electrons

Second Shell

higher in energy, farther away from the nucleus, and can hold up to eight electrons

Third Shell

higher in energy than the first and second shells, even farther away from the nucleus, and can hold up to 18 electrons

Note

there are other higher shells, but they are not dealt with in organic chemistry

Electron apartments

Orbitals

Orbitals

electron shells are further subdivided into these; they are the actual location in which an electron can be found

Shell

indicates the energy level of a certain electron; a full shell will be spherical in shape

Orbital

status the actual location in space of where the electron resides

Electron Shell

Floor in the apartment complex (energy level)

Orbital

Apartment where the electron resides

Heisenberg uncertainty principle

the uncertainty in knowing the locations of electrons at a given moment

s orbital

spherical in shape

p orbital

shaped like a dumbbell

1s orbital

spherically symmetric, holds 2 electrons, only orbital in the first shell

Second Shell

contains both s and p orbitals, holds up to 8 electrons

2s orbital

spherical shape like 1s orbital, but larger and higher in energy

2p level

consists of 3 individual p orbitals

Px

an orbital that points in the x direction

Py

an orbital that points in the y direction

Pz

an orbital that points in the z direction

Electron instruction manual

Electron configuration

Ground-state electron configuration

list of orbitals occupied by electrons in a particular atom

Hunds rule

the electrons should go into different orbitals with the same spin, instead of pairing up into a single orbital with the opposite spin

Example

Carbons electron configuration is 1s^2 2s^2 2px^1 2py^1 2pz^0 (not 1s^2 2s^2 2px^2 2py^0 2pz^0, which violates Hunds rule)

Atom Marriage

Bonding

Noble gases

the only atoms that have their outermost shells filled with electrons; unreactive

Octet rule

the desire of atoms to have filled electron shells

Valence electrons

electrons in the outermost shell of an atom; most important for bonding

Core electrons

electrons in the inner shells; dont participate in bonding

To Share or Not to Share

Ionic and Covalent Bonding

Ionic Bonding

two electrons in a bond are not shared between the bonding atoms

Covalent Bonding

two electrons in a bond are shared between the two bonding atoms

Example of covalent bonding

hydrogen gas (H2)

Electronegativity

tendency of an atom to attract electrons towards itself

Ionic bond

when the electronegativity difference is very large; greater than 2

Polar covalent bond

if the electronegativity difference is smaller; between 0 and 2

Purely covalent bond

if the electronegativity difference is 0

Inorganic compounds

non-carbon-containing compounds

Separating Charge

Dipole Moments

Dipole moment

separation of charge in the bond because the more electronegative atom "bullies" most of the bonding electrons away from the less electronegative atom

For example

in hydrochloric acid (HCl), chlorine is the more electronegative atom of the two, so the electrons between hydrogen and chlorine are "hogged" mostly by chlorine

Dipole vector

a distinct arrow that is used to show the direction of the dipole moment, or separation of charge

Problem solving

Predicting bond dipole moments

Problem Solving

Predicting molecule dipole moments

VSEPR theory

stands for valence shell electron pair repulsion; predicts the approximate geometry of bonds around an atom

Linear

180°