Sci Q2 Chapter 1

Atoms

Atoms

smallest unit of matter; building block of the universe

atomic structure

the atom consists of three component parts: Protons, Electrons, and Neutrons

Who discovered the electron?

JJ Thomson in 1897

Who discovered the proton?

Eugen Goldstein in 1886 (Rutherford 1917)

Who discovered the neutron?

James Chadwick in 1932

Who discovered the nucleus?

Ernest Rutherford in 1911

Democritus (400 BC)

greek philosopher that said all matter is made of tiny particles called "atomos" or atoms

John Dalton's Atomic Model

(billboard) all matter is composed of atoms; atoms cannot be divided

John Dalton developed his atomic structure

because of his nitric oxide experiment

JJ Thomson developed his atomic structure

by using the cathode ray tube

J.J. Thomson's Atomic Model

(plum pudding) atoms is made up of electrons floating in protons

Ernest Rutherford's Atomic Model

(nuclear) atoms have nucleus surrounded by electrons; he discovered nucleus

Ernest Rutherford developed his atomic structure

through gold foil experiment

Neil Bohr's Atomic Model

(planetary) electrons move in fixed orbit (s

Neil Bohr developed his atomic structure

through atomic spectra

Erwin Schrodinger's Atomic Model

(quantum model) this doesn't accurately tell us where an electron is

Werner Heisenberg and the uncertainty principle

posited the "uncertainty principle" no human could ever determine the path of an electron because observing the electron with light affected the location: we couldn't accurately predict anything physical.

principal quantum number

indicated the size of an electron

azimuthal quantum number

tells us the shapes of the electron orbitals (sphere

magnetic quantum number

indicates the orientation of an orbital around the nucleus (up or down)

spin quantum number

indicate the two fundamental spin states of an electron in an orbital (clockwise/counterclockwise)

quantum numbers

it gives us the idea how electrons behave; used to completely describe all the attributes of a given electron belonging to an atom

electron configuration

representation of the arrangement of the electrons distributed among the orbital shells and subshells

s, p, d, f orbitals

s shell: can hold 2 electrons per energy level \n \n p shell: can hold 6 electrons per energy level \n \n d shell: can hold 10 electrons per energy level \n \n f shell: can hold 14 electrons

electron configuration notation

numbers of electrons are represented by adding a superscript to the sublevel designation

1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p 6s 4f 5d 6p 7s 5f 6d 7p

3 principles of electron configuration

Aufbau Principle; Pauli Exclusion; Hunds rule

Anfbau principle

electrons fill lower-energy atomic orbitals before filling higher-energy ones. (aufbau - means building up)

Pauli Exclusion Principle

states that a maximum of two electrons can occupy a single atomic orbital but only if the electrons have opposite spins

Hund's Rule

every orbital in a sublevel is singly occupied before any orbital is doubly occupied

Periodic Table

tabular display of the chemical elements; it is arranged in increasing atomic number

Ion

a charged atom

atomic number and mass

atomic number - protons; atomic mass - protons and electrons

series/periods

horizontal arrangement; rows (1-7)

family/group

vertical arrangement; column (1-18)

1A - 8A

representative elements (s and p elements)

1B - 8B

transition elements (d elements)

inner transition elements

latanites (57 - 71) and actinites (89 - 103)

alkali metals

group 1A

alkali earth metals

group 2A

halogens

group 7A

noble gases

group 8A

valence electrons

electrons on the outermost shell

electronegativity

tendency of an atom to attract electrons; non-metals have higher electronegativity

ionization energy

the amount of energy needed to remove an electron from an atom; non-metals have higher ionization energy

octet rule

atoms tends to prefer to have 8 electrons to be stable; non-metals have higher tendency (we do not consider the f and d electrons)

lewis dot symbol

element surrounded by dots that represent its valence electrons. the number of dots in the Lewis dot symbol is the same as the number of valence electrons, which is the same as the last digit of the element's group number in the periodic table.