Atomic Structure and Periodicity - Unit Test Review

Includes: Theories of Atomic Structure, Isotopes: Average atomic mass and determine % of abundance, Modern Atomic Theory: quantum Mechanic Modal of Atom( wave modal), Emission Spectra, Electron Configuration: ground state , noble gas and Orbital Notation, Periodic Table – classification and blocks, Periodic Trends

Dalton’s atomic theory

Explained conservation of mass as the combination, separation, or rearrangement of atoms

John Dalton

• Matter is composed of small particles called atoms

• Atoms are indivisible and indestructible (proven false)

• Atoms of a given element are identical in every way (proven false: isotopes)

• Atoms of different elements are different

• Different atoms combine in a whole number ratios to make compounds

Atoms

The smallest particle of an element that retains its properties of the element

Cathode Ray

When electric charge is applied, a ray of radiation travels from cathode to anode

Electrons

Particles carrying a negative charge

JJ Thomson

man who created the cathode ray tube and discovered electrons

Also came up with the plum pudding model

Robert Milikan

man who used the oil drop apparatus to determine the charge of an electron (coulombs)

Ernest Rutherford

studied how positively charged alpha particles interacted with solid matter using the gold foil experiment

• atoms are mostly empty space

• if they pass through, they go between the nucleus and the electronic field

• opposite charges attract

Democritus

• All things are composed of the atomos or the fundamental particles, atoms

• Atoms cannot be destroyed

• Atoms are separated by the void or empty space

• Atoms are in constant motion and undergo constant change through the void.

HIs theories weren’t widely accepted at the time because of Aristotle’s more popular ideas

Aristotle

argued that the four elements were not composed of atoms but were continuous forms of matter. He also denied that a 'void' between atoms could exist.

Coloumbs

measuring unit of electron charge

Atomic Number

The number of protons in an atom. All atoms of the same elment have the same number of protons

Isotopes

Atoms of the same element that have a different number of neutrons

Mass Number

The weight of the atom and the total number of protons and neutrons combined.

Isotopic Notation

_{^A z} X

A = Mass number

z = Atomic number

x = Chemical Symbol

Hyphen Notation

C-12, C-14

Atomic Mass unit (amu)

1/12 the mass of a carbon-12 atom. (the approximate weight of a proton or a neutron)

Nuclear Fission

The splitting of a heavy nucleus into 2 small nuclei

Isotope Abundance Formula

(isotope atomic mass)(% abundance in decimal form) + (isotope atomic mass)(% abundance in decimal form)

Nuclear Fusion

Combining 2 light nuclei to forma heavier and more stable nucleus

Ion

any atom that bears one or more positive or negative electrical charge

Cation

Positive ions

Anions

Negatively charged ions

Electron cloud structure

Electrons within clouds have different amounts of energy

Electromagnetic radiation

a kind of radiation including visible light, radio waves, gamma rays, and X-rays, in which electric and magnetic fields vary simultaneously.

Wavelength

λ symbol

Shortest distance on points on a continuous wave (meters)

Frequency

v symbol

Number of waves/second (hertz)

Amplitude

Height from the origin to the crest

Speed of light

c symbol

3.00 ×10⁸ m/s

understando

c = λ/v

understando?

Quantum

minimum amount of energy gained or lost by an atom

Plancks Constant

h symbol

6.636e-34 J * S

Alles klar

E quantum = hv

alles klar?

Photoelectric effect

when electrons are emitted from a metal surface when light of a certain frequency shines on it

Photon

light particle with no mass, only energy

Todo Claro

E photon = hv

todo claro?

Atomic Emission Spectrum

Set of frequencies of the Em waves emitted by atoms of the element

Ground State

the lowest allowable energy state of an atom

Excited state

a state of a physical system, such as an atom, molecule, or nucleus, that has more energy than its ground state

Quantum Numebr

The number given to an orbit

Electron Configuration

The arrangement of electrons

Heisenburg uncertainty principle

Its impossible to know the velocity and position of a particle aat the same time (only probability)

Quantum Mechanical model

Model in which schrödinger treats electrons as waves

Principal Quantum Number (n)

relative size and energy of atomic orbitals

Principal Energy levels

Atoms major energy levels

energy sublevels

Contained within the principel energy levels

Aufbau principle

states that each electron occupies the lowest energy orbital available

Pauli exclusion principle

2 electrons can occupy one orbital if they have opposite spins

Hund’s Rule

Single electrons with the same spin must occupy equal energy orbitals before additional electrons with opposite spins can occupy the same energy level orbitals

TO DUMB IT DOWN: You have to put one electron in each “room” before adding another in the first sub-level

Valence electrons

Electrons in the outermost orbital (highest energy level)

Electron-dot Structure

The element’s sumbol (representing the nucleus) surrounded by the dots representing the valence electrons

• Also called the lewis structure

Orbital Notation

offers a visual account with boxes and arrows to depict electrons and their spins in respective orbitals

Cu, Ag, Cr, Mo, Au

The exceptions to regular electron configuration rules

Noble Gas Notation

an abbreviated notation of an atom's electron configuration.

The _____ ___s's electron configuration is substituted and replaced with the elemental symbol in brackets.

Periodic Law

Periodic repittion of chemical and physical properties of the elmeents when increasing atomic number

Group

Columns of elements

Periods

Rows of elements

Representative elements

Elements in groups 1, 2, 13 - 18 that have a wide variety of chemical/physical properties

Transition elements

Elements in groups 3-12. Can be metals, non-metals, and metalloids

Metals

Generally shiny, when clean and smooth, solid at room temperature. Good conductors

Alkali metlas

reactive elements in group 1 (except for hydrogen)

Alkaline Earth Metals

Reactive metals of group 2

Inner transition metals

The lanthanide and actinide series

Non-metals

Gases or dull-looking, brittle solids. Good insulators

Halogens

Highly reactive elements in group 17

Noble Gases

Unreactive gases in group 18

Metalloids

Elements woth both physical and chemical properties of metals and nonmetals

S-block

What block is this

P-block

what block includes groups 13-18 (except for helium)

d-block

what block includes groups 3-12

f-block

What block includes the lanthanide and actinide series

Atomic Radius

Periodic trend - half the distance between nuclei or identical atoms

Decreases across the period and increases down the group

Ion size

Decreases as you move across the period and increases down the group

Ionization energy

The energy needed to remove an electron (measured in joules)

increases across the period and decreases down the group

Octet rule

Atoms gain or lose or share electrons to get a set of 8 valence electrons

(metals = 4+, non metals = 4-)

Electronegativity

The ability to attract electrons

Increases across a period and decreases down the group