7.6: Test: Bohr to Quantum Model of Atoms, Electron Configurations, Periodic Table and Periodicity

energy levels

the fixed energies an electron can have

What did Bohr propose in his model of the atom?

Bohr proposed that an electron is found only in specific circular paths, or orbits, around the nucleus.

Quantum (of energy)

the amount of energy required to move an electron from one energy level to another energy level

quantum mechanical model

the modern description of the electrons in atoms

Where did the quantum mechanical model come from?

the mathematical solutions to the Schrodinger equation

What does the quantum mechanical model determine about the electrons in an atom?

The quantum mechanical model determines the allowed energies an electron can have and how likely it is to find the electron in various locations around the nucleus of an atom

what do atomic orbitals describe?

describes the probability of finding an electron at various locations around the nucleus

What are atomic orbitals?

mathematical expressions from the Schrodinger equation

How do sublevels of principal energy levels differ?

each energy level corresponds to one or more orbitals of different shapes. The orbitals describe where an electron is likely to be found.

What is the shape of an s orbital?

sphere

What is the shape of a p orbital?

dumbbell

what is the shape of a d orbital?

four-leaf clover

how many sublevels are in principal energy level n=1?

1 sublevel

how many sublevels are in principal energy level n=2?

2 sublevels

how many sublevels are in principal energy level n=3?

3 sublevels

how many sublevels are in principal energy level n=4?

4 sublevels

how many electrons can be stored in an s orbital?

2 electrons

how many electrons can be stored in a p orbital?

6 electrons

how many electrons can be stored in a d orbital?

10 electrons

how many electrons can be stored in an f orbital?

14 electrons

What is the maximum number of electrons principal energy level n1 can hold?

2 electrons maximum

What is the maximum number of electrons principal energy level n2 can hold?

8 electrons maximum

What is the maximum number of electrons principal energy level n3 can hold?

18 electrons maximum

What is the maximum number of electrons principal energy level n4 can hold?

32 electrons maximum

electron configurations

the ways in which electrons are arranged in various orbitals around the nuclei of atoms

what are the three rules for writing the electron configurations of elements?

the aufbau principle, the Pauli exclusion principle, and Hund's rule

Aufbau Principle

electrons occupy the orbitals of lowest energy first

Pauli Exclusion Principle

An atomic orbital may describe at most two electrons (with opposite spin)

Spin

a quantum mechanical property of electrons that may be thought of as clockwise or counterclockwise (indicated with arrows)

Hund's Rule

electrons occupy orbitals of the same energy in a way that makes the number of electrons with the same spin direction as large as possible

P Block

What is the orbital order?

1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p

S Block

D Block

F Block

amplitude

the wave's height from zero to the crest

Wavelength (λ)

the distance between crests of a wave

frequency (ν)

the number of wave cycles to pass a given point per unit of time

Hertz (Hz)

Unit for frequency, SI unit of cycles per second

electromagnetic radiation

energy waves that travel in a vacuum at a speed of 2.998 x 10^8 m/s; includes radio waves, microwaves, infrared waves, visible light, ultraviolet waves, X-rays, and gamma rays

spectrum (of colors)

wavelengths of visible light that are separated when a beam of light passes through a prism; range of wavelengths of electromagnetic radiation

What causes atomic emission spectra?

When atoms absorb energy, their electrons move to higher energy levels. These electrons lose energy by emitting light when they return to lower energy levels.

atomic emission spectrum

the pattern formed when light passes through a prism or diffraction grating to separate it into the different frequencies of light it contains

Planck's Constant (h)

(6.626 x 10^-34 Js) Used to calculate the radiant energy absorbed or emitted by a body based on the frequency of radiation

Photoelectric Effect

the ejection of electrons by certain metals when they absorb light with a frequency above a threshold frequency

How did Einstein explain the photoelectric effect?

He proposed that light could be described as quanta of energy that behave as if they were particles.

Equation for energy

E = hv

Photons

a quantum of light; a discrete bundle of electromagnetic energy that interacts with matter similarly to particles

Ground State

The lowest possible energy of an atom (described by quantum mechanics)

How are the frequencies of light emitted by an atom related to the changes of electron energies?

the light emitted by an electron moving from a higher to a lower energy level has a frequency directly proportional to the energy change of the electron

How does quantum mechanics differ from classical mechanics?

Classical mechanics adequately describes the motions of bodies much larger than atoms, while quantum mechanics describes the motions of subatomic particles and atoms as waves

Heisenberg uncertainty principle

it is impossible to know exactly both the velocity and the position of a particle at the same time

How did chemists begin to organize the known elements?

used the properties of elements to sort them into groups

How did Mendeleev organize his periodic table?

Arranged the elements in order of increasing atomic mass

How is the modern periodic table organized?

arranged in order of increasing atomic number

periodic law

when the elements are arranged in order of increasing atomic number, there is a periodic repetition of their physical and chemical properties

What are 3 broad classes of elements?

metals, nonmetals, metalloids

Metals

elements that are good conductors of heat and electric current. tend to be ductile, malleable, and shiny

Nonmetals

elements that tend to be poor conductors of heat and electric current. properties opposite of metals.`

Metalloids

elements that tend to have properties of both metals and nonmetals

What information can be displayed in a periodic table?

The periodic table usually displays the symbols and names of the elements along with information about the structure of the atom

alkali metals

any metal in Group 1A of the periodic table

alkaline earth metals

any metal in Group 2A of the periodic table

halogens

a nonmetal in Group 7A of the periodic table

transition metal

one of the Group B elements in which the highest occupied s sublevel and a nearby d sublevel generally contain electrons

How can elements be classified based on electron configurations?

elements can be sorted into noble gases, representative elements, transition metals, or inner transition metals based on their electron configurations

noble gases

an element in Group 8A of the periodic table; the s and p sublevels of the highest occupied energy level are filled

representative elements

an element in an "A" group in the periodic table; as a group these elements display a wide range of physical and chemical properties. In their atoms, the s and p sublevels in the highest occupied energy level are partially filled

inner transition metals

an element in the lanthanide or actinide series; the highest occupied s sublevel and nearby f sublevel of its atoms generally contain electrons; also called inner transition element

atomic radius

one-half the distance between the nuclei of 2 atoms of the same element when the atoms are joined (r = d/2) (r = bonded atomic radius)

What are the trends among the elements for atomic size?

In general, atomic size increases from top to bottom within a group and decreases from left to right across a period

ion

An atom or group of atoms that has a positive or negative charge.

how do ions form?

Positive and negative ions form when electrons are transferred between atoms

cation

any atom or group of atoms with a positive charge

anion

any atom or group of atoms with a negative charge

ionization energy

the energy required to remove an electron from its atom in its gaseous state

What are the trends among the elements for first ionization energy?

first ionization energy tends to decrease from top to bottom within a group and increase from left to right across a period

what are the trends among the elements for ionic size?

ionic size tends to increase from top to bottom within a group and (the size of cations and anions) decrease from left to right across a period

Electronegativity

the ability of an atom to attract electrons when the atom is in a compound

what are the trends among the elements for electronegativity?

In general, electronegativity values decrease from top to bottom within a group. For representative elements, the values tend to increase from left to right across a period