Unit 3-Atomic Structure through Nuclear Model

Democritus said all matter is composed of two things_______

Atoms and the void

he word,atom derives from the Greek word atomos, which means

indivisible

True or False-All matter consists of particles in space

true

True or False-Atoms have motion

true

True or False-Atoms are indivisible

false

True or False-Existing things differ because of the shape and arrangement of their atoms

true

True or False- Atoms make life predictable because every event results from a collision of atoms

false

William Gilbert proved that opposite charges and like charges________

are attracted

Charles Agustin Coulomb developed Coulomb's law which states that______

The force of attraction between 2 charged particles varies inversely to the square of the distance between them.

Antoine Lavoisier used a sealed combustion chamber to show The Law of Conservation of Mass which is

the mass of reactants = the mass of the products

Joseph Proust proposed that elements combine in_______proportions to form a specific compound.

constant

How many parts are in Dalton's Atomic Theory

5

Matter is made up of ____ with ________ in between them

individual particles, spaces

The particles of an element are ______ to each other

identical

Atoms are indivisible true or false

false

Ture or False- there are as many kinds of atoms as there are elements

true

The atoms of one element cannot be converted into

atoms of another element

Atoms are neither created nor destroyed in chemical reactions, merely _____

rearranged

Dalton also gets credit for discovering the Law of_____

Multiple Proportions

Law of Multiple Proportions

elements combine in more than one ratio to form different compounds

Cathode ray tube

glass tube from which most of the air has been evacuated

Cathode

negatively charged plate

The cathode ray is attracted to the _______ charged plate

positively

Anode

Positively charged plate

Where does the ray go?

The ray travels through a hole in the anode plate and to the fluorescent screen where it produces a bright light.

What happens when an electric field is applied to the cathode ray tube

the cathode ray is attracted to the plate with the positive charge.

electrons

Negatively charged particles

Millikan determined the ________ of the electron

charge

A fine mist of ____ was sprayed into the upper chamber with an atomizer

oil

Some of the oil droplets fell through the ____ in the _______

hole, upper floor

Millikan used _______ to ionize gas molecules in the chamber

an x-ray

Electrons were able to stick to the oil droplets. The oil droplets then carried a _____ charge

negative

As the voltage across the plates increases, the velocity of the oil droplets _____

slows

As the voltage across the plates increases, the velocity of the oil droplets______

slows

As the voltage increases more, some oil droplets are able to move upward towards the __________ plate

positive

When the voltage is set just right, an oil drop can be ___________

suspended

Who invented the Plum Pudding Model

JJ Thomson

What are the plums in the plum pudding model

the electrons

How did Thomson know the dough of the model was positively charged even though no one had proven the existence of positively charged parts of the atom?

atoms=0 so they have to add up to equal 0

rutherford used alpha particles in his experiment with the gold foil. What made the alpha particles useful for his experiment?

They are fast,big and positively charged

Rutherford concluded that most of the atom is empty space what about his results support this conclusion

The particles that went through the gold foil

Rutherford also concluded that the atom has a dense, positive core. What about his results support this conclusion?

The ones that scattered because they are positive and bouncing and bumping away

what was the problem with the Rutherford model

the mass of the atoms didn't add up and the nucleus should be unstable

What does the atomic number represent?

number of protons

Where is the atomic number on the isotope symbol

below the symbol on the left

How is the mass number determined

# of protons + # of neutrons

Which corner of the isotope symbol contains the mass number

upper left

What happens to the total mass of a system during a chemical reaction

the mass is conserved reactions=products

What does "fixed composition" mean with regard to chemical compounds.

Compound made up of the same elements in the same ration

What are the 3 basic particles in an atom

protons, neutrons & electrons

Atom

a particle of matter that defines a chemical element

Molecule

A group of atoms bonded together

Element

A substance that cannot be broken down into simpler substances

Compound

a substance that is formed by chemically combining elements

Mixture

A combination of two or more substances that are not chemically combined

Solution

homogeneous mixture

Describe Dalton's model of the atom.

~ Tiny ball model
~ it looked like a sphere

Describe the plum pudding model

-Hard inside of protons and neutrons
-Electrons around it

Describe the nuclear model

Positively charged nucleus in a cloud of negative electrons.

Most of the atom is empty space.

Law of Conservation of Matter

Matter is not created nor destroyed in any chemical or physical change

Law of Constant Composition

A given compound always contains elements in exactly the same proportion by mass

Where are protons located

inside the nucleus

Where are Neutrons located

inside the nucleus

Where are electrons located?

outside the nucleus

Charge of a proton

positive

Charge of Neutron

neutral

Charge of Electron

negative

mass of proton

1 amu

Mass of a Neutron

1 amu

Mass of an electron

0 amu

isotope

Atoms of the same element that have different numbers of neutrons

What causes the difference in isotopes

the # of neutrons

Ion

A charged atom

What subatomic particles are responsible for the charge of an atom or ion

The Protons and Neutrons

Cations

positively charged ions

Anions

negatively charged ions

If you add or subtract a proton from an atom, what will it be and how will it be different?

It will become an atom of a different element with a different atomic #

If you add a atom to another atom, what will it be and how will it be different

It will become a molecule with a different identity

If you add or subtract a neutron from a atom, what will it be and how will it be different?

It will be an isotope with a different mass #

If you add or subtract an electron from an atom what will it be and how will it be different?

It will be an ion with a different charge