Unit 1 - Level 2 Mastery Check 🧪🧬

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These two people said that the atom was indivisible.

These two people said that the atom was indivisible.

John Dalton (1803) and Democritus (450 BC)

Democritus theorized the existence of the _____.

Atom

Democritus thought that there was only four ‘elements’. What were they?

Fire, Water, Air, Earth

John Dalton discovered that all of these for one element are the same.

Atoms

This person said that atoms are neither created nor destroyed in a chemical reaction. He also said that in a chemical reaction atoms are separated, _________d, or _________d.

John Dalton

Combined

Rearranged

This person discovered the ________ using the cathode ray tube. He also determined that it was smaller than a _________ atom.

J. J. Thomason

Electron

Hydrogen

J. J. Thomason knew that the atom was _________ and the electron was ________, so there must be positive material along with a lot more mass.

Neutral

Negative

Who was the person who made the Plum Pudding or Chocolate Chip Cookie Model?

J. J. Thomason

This person did a famous gold foil experiment (a.k.a. the ________ __________ experiment.

Ernest Rutherford

Alpha Scattering Experiment

Ernest Rutherford calculated that the atom has a small, dense, positively charged, _______ly-located nucleus surrounded by ________ly charged electrons.

Centrally

Negatively

Ernest Rutherford in 1919 called the positive particles _________s.

Protons

These 2 people sort of collabed in 1932 and showed that the nucleus also had ________s.

Ernest Rutherford and James Chadwick

Neutrons

This person concluded that these moved around the nucleus in definite orbits or _______ levels.

Neils Bohr (1914 - Was before Rutherford + Chadwick)

Electrons

Energy

What shape is the current atop?

A Sphere

The current atom has a positive nucleus containing ________s and ________s.

Protons

Neutrons

The “nucleus” of the current atom has neutral neutrons and postitive protons and ___% of the mass.

99.9%

Since atoms are electrically neutral, the number of protons must be ______ to the number of electrons

Equal

There are how many elements in the periodic table?

118

This is the smallest piece of matter that still retains the properties of that matter. It makes up everything!

An Atom

This is the center of the atom and contains two particle types. It l’os has a positive charge.

Nucleus

This rounds the nucleus. It contains only one particle type. It has a negative charge

Electron Cloud.

What is the abbreviated version of a proton?

p+

What is the abbreviated version of a neutron

nº

What is the abbreviated version of an electron?

e-

All of these are identical. They locate in the nucleus of the atom. Their charge is positive.

Protons

All of these are identical. They locate in the nucleus. Their charge is neutral.

Neutrons

These locate in the electron cloud. Their charge is negative.

Electron

What is the relative mass of an electron?

1/1840 amu

What is the relative mass of a proton?

1 amu

What is the relative mass of a neutron

1 amu

“Z” is equal to the _______ number

Atomic

“A” is equal to the _______ number

Mass

Atomic Number = # of _________s

Protons

The atomic number determines the ________y of the element. On the periodic table, it starts with ______ and goes up in order.

Identity

One

Atomic Mass = the ________ of the masses of the isotopes of an atom.

Average

The atomic mass is not the masses of ________s, _________s, and ________s added together.

Protons, neutrons, and electrons.

Mass Number = # of ________s and ________s.

Neutrons, Protons

Take the _______ number (round) of the atomic mass to get the mass number.

Whole

When is an atom neutral?

When the # of protons = the # of electrons

When is the atom positive?

When protons are greater than electrons

When is an atom negative?

When the electrons are greater than the protons

If you want to change the identity of the element you add a what?

Proton

If you want to change the charge of your atom you can add a what?

Neutron

If you want to change the mass of your atom you can add a what?

Proton or Neutron

Isotopes are atoms of the _____ ______ that have a different number of neutrons.

Same element

To identify an isotope, you write the element’s name and you follow with it’s _______ ________.

Mass Number

To calculate the atomic mass, you have to know the isotope’s mass numbers and the _______ abundance of each.

Percentage

Most isotopes are stable but ______ isotopes are unstable and break down into more stable forms by ______ing particles and energy.

Radioactive

Emitting

What is an isotope?

Isotopes are atoms with the same number of protons, but different number of neutrons.

How can you tell isotopes apart?

By determining the number of neutrons they have.