Unit 1 - History of Chemistry

Alpha particle behave like what other particles?

-Helium atoms stripped of their electrons

-A charged species

First person to name an atom?

Democritus

-atomos (indivisible)

4 original Greek elements were...

-earth

-air

-fire

-water

Most reactive nonmetal group?

Halogens or group 17

Buckyball formula and full name is?

-C60

-buckminsterfullerene

3 forms of carbon are...

-diamond

-graphite

-buckyball

What did Henry Mosely do?

He defined what atomic number meant which rearranged the periodic table and made it what it is today

Who was the father of the periodic table?

Dmitri Mendeleev

What does amu stands for?

atomic mass unit

What was the name of Bohr's atomic model?

planetary model

What was the name of JJ Thomson's atomic model?

Plum pudding model or chocolate chip cookie

Who discovered neutrons?

James Chadwick

JJ Thomson discovered electrons by...

He used the Cathode Ray Experiment, where he put a magnet to a cathode ray and observed that the ray attracted and repelled, meaning that ray must have a charge.

What is electrolysis and what was it used to discover?

a bunch of elements: H,O

• Means splitting by electricity 

  • Electro - means electricity

  • Lysis - means to split

What did the gold foil experiment discover about atomic structure?

Existence of a small dense positively charged nucleus

Group 18 is called...

Noble gases

What was Proust's Law?

Law of definite proportions

What was Dalton's Law?

Law of partial pressure

Millikan discovered the...

exact charge and mass of e-

John Dalton

Developed John Dalton Theory. 4 Postulates

-all elements are composed of atoms

-Atoms of the same element are identical. Atoms of differing elements are different

-Atoms of different elements can physically/ chemically mix together to form compounds

-Atoms cannot be created nor destroyed

How did Democritus discover the atom?

He cut up a stone into small pieces and each piece had the same properties as the original. Suggested that atoms were eternal and could not be destroyed.

What famous experiment did Millikan conduct

The Oil Drop Experiment

Who did the gold foil experiment?

Ernest Rutherford

How did the gold foil experiment work?

A beam of alpha particles was shot at a sheet of gold foil, and a few of those particles were deflected

What did Niels Bohr do?

He made contributions to understanding atomic structure and quantum theory

How was Mendeleev's periodic table arranged?

By increasing atomic mass and left spaces where undiscovered elements would fit

Modern Atomic Theory

Electrons are not in set paths, but are constantly changing paths as they move around the nucleus. We know regions where they are likely to be, called electron clouds.

Bohr Model

Electrons orbit the nucleus in set paths that relate to their energy level. Electrons may change paths by gaining or losing energy.

What is Group 1 called?

Alkali metals

How are groups arranged?

Vertical

How are periods arranged?

Horizontal

Which group are the alkaline earth metals?

Group 2

Group 17 properties:

all poisonous gases, most reactive group of non-metals, contains elements in all 3 states of matter at room temperature

Group 18 properties:

Not very reactive, odorless, colorless

______ charges are usually reversible.

Physical

A pure substance is either a ______ or ______.

element or compound

A physical combination of two or more substances is a ________.

mixture

Chemistry is a natural science that deals with __________.

matter

Matter is anything that has _______ and occupies _______.

mass, space

Matter exists in 3 states

Solid, liquid, gas

______ will change depending on how much of the substance you have.

Extensive

_______ changes are not easily reversible.

Chemical

Compounds are made up of _____, which are always present in the same _____ in a given compound.

elements, ratio

______ properties will be the same regardless of the quantity.

Intensive

s orbitals are _____.

spherical

p orbitals are ____ shaped.

dumbbell

d orbitals are mostly _____ shaped.

clover

Aufbau principle

An electron occupies the lowest-energy orbital that can receive it.

Hund’s rule

• Orbitals of equal energy are each occupied by one electron before any orbital is occupied by a second electron.

• All electrons have the same spin (up)

Chemical:

any substance that has a definite composition.

Atom:

the smallest unit of an element that maintains the chemical identity of that element.

Element:

a pure substance that cannot be broken down into simpler, stable substances and is made of one type of atom.

Subatomic:

smaller than an atom

Compound:

a substance that can be broken down into simpler stable substances. Each compound is made from the atoms of two or more elements that are chemically combined (or chemically bonded).  

Molecule:

the smallest unit of an element or compound that retains all of the properties of that element or compound.

Are mass and volume intensive or extensive properties?

Extensive

Are density and color intensive or extensive properties?

Intensive

Homogeneous mixtures:

Mixtures that are uniform in composition. They have the same proportion of components throughout and are also called solutions.

Heterogeneous mixtures:

Mixtures that are not uniform throughout. 

Law of Conversation of Mass:

Matter cannot be created nor destroyed in any chemical reaction only rearranged. 

Three types of radiation in order of least dangerous to most:

alpha, beta, gamma

What was used to discover protons?

Canal rays

What side of the periodic table are metals found on?

Left

Law of Chemical Periodicity

Physical and chemical properties of the elements recur in a systematic and predictable way when the elements are arranged in order of increasing atomic number.

What are the names for the two rows (series) at the bottom of the table?

Lanthanide series and Actinide series

What is an allotrope?

When one element like carbon can exist in several forms.

What is the name of the Group 16 elements?

Chalcogens