chem 4-5

amplitude
waves height from zero to the crest

wavelength
distance between two crests

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

ROYGBIV
visible colors in order from lowest frequency to highest frequency

aufbau principle
electrons occupy the orbitals of the lowest energy levels first

pauli exclusion principle
an atomic orbital may describe at most 2 electrons

hunds rule
When electrons occupy orbitals of equal energy, one electron enters each orbital until all the orbitals contain one electron with the same spin direction

Atom
the smallest particle of an element that retains it’s identity in a chemical reaction

Democritus
who reasoned that atoms were indivisible and indestructable?

Dalton’s atomic theory
1. all elements are composed of tiny indivisible particles called atoms
2. atoms of the same element are identical. the atoms of any one element are different from those of any other element.
3. atoms of different elements can physically mix together or can chemically combine in simple whole-number ratios to form compounds
4. chemical reactions occur when atoms are seperated from each other, joined, or rearranged in a different combination. atoms of one element, however, are never changed into atoms of another element as a result of a chemical reaction.

scanning electron microscopes
What instruments are used to observe individual atoms?

protons, electrons, neutrons
What are the three types of subatomic particles?

Electron
negatively charged subatomic particle

cathode
an electrode with a negative charge.

Thomson
Found that cathode rays are attracted to metal plates that have a positive electrical charge.

protons
a positively charged subatomic particle found in the nucleus of an atom

neutrons
a subatomic particle with no charge and a mass of 1 amu; found in the nucleus of an atom

Dalton
used experimental methods to propose an atomic theory based on earlier ideas

nucleus
the small core known as a … is in the center of an atom which contains protons and neutrons

empty space
Most of the volume of an atom is occupied by what?

protons
the identity of an element is determined by the number of … it contains?

atoms
each of an element’s … has a different number of neutrons and a different mass number

atomic mass
the … of an element is the weighted average of all the isotopes of the element.

cathode ray
a glowing beam traveling between charged electrodes

Rutherford
found that most of an atoms mass is in the nucleus, and that electrons surround the nucleus

Bohr
found that electrons are arranged in concentric circular paths around the nucleus

energy levels
What are the fixed energies of electrons called?

farther
In general, the higher the electron is on the energy ladder, the … it is from the nucleus.

quantum mechanical model
a mathematical model of the atom.

previous models of the atom
physical models based on the motion of large objects

atomic orbital
often thought of as a region of space in which there is a high probability of finding an electron.

S
what letter is used to denote a spherical orbital?

2
What is the maximum number of electrons an s orbital can have?

1
how many orbitals does s contian?

3
how many orbitals does p contain?

5
how many orbitals does d contain?

7
how many orbitals does f contain?

6
What is the maximum number of electrons p can have?

10
What is the maximum number of electrons d can have?

14
What is the maximum number of electrons f can have?

stable
filled energy sublevels are more … than partially filled sublevels.

filled
Half-filled levels are not as stable as … levels, but are more stable than other configurations.

hertz
The units of frequency are usually cycles per second. The SI unit of cycles per seconds is called a …

constant
the product of wavelength and frequency always equals a … , the speed of light

radio waves, microwaves, infrared waves, visible light, ultraviolet waves, x-rays, and gamma rays
What kinds of visible and invisible radiation are included in the electromagnetic spectrum?

radio waves
What type of radiation has the lowest frequency?

gamma rays
What type of radiation has the highest frequency?

they emit light (because the atoms absorb the energy)
What happens when an electric current is passed through the gas or vapor form of an element?

atomic emission spectrum
Passing the light emitted by an element through a prism gives the … of the element.

higher… lower
Only electrons moving from … to … energy levels lose energy and emit light

photons
What did Albert Einstein call the quanta of light energy?

ground state
What is the lowest possible energy of an electron called?

Planck’s Constant
a number used to calculate the radiant energy (E) 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.

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

all moving objects have wavelike behavior
What does de Broglie’s equation predict about the behavior of particles

velocity… position
According to the Heisenberg uncertainty principle it is impossible to know exactly both the … and the … of a particle at the same time

No (it applies only to small particles)
Does the Heisenberg uncertainty principle apply to cars and airplanes?

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

quantum mechanical
The … model describes the energy an electron can have and the probability of finding the electron in various locations around the nucleus of an atom

sublevels
Orbitals, which are found in … , have different shapes, depending on the energy of the electrons they contain

aufbau principle
Electron configurations can be written by using the … , the Pauli exclusion principle, and Hund’s rule

energy levels
When atoms absorb energy, their electrons move to higher…

quanta
describing light as … of energy that behave as particles helps to explain the photoelectric effect

frequency
When an electron drops to a lower energy level, it emits light that has a … directly proportional to the energy change of the electron

classical mechanics
describes the motion of large bodies

quantum mechanics
describes the motion of very small particles, such as subatomic particles.

Tags: