Chemistry Unit 2 Test Flashcards

Proton ; location ; charge symbol ; mass

Subatomic particle ; nucleus ; p+ ; 1 amu

Neutron ; location ; charge symbol ; mass

Subatomic particle ; nucleus ; n⁰ ; 1 amu

Electron ; location ; charge symbol ; mass

Subatomic particle ; orbital ; e- ; amu undetermined

Law of Definite Proportions

Every sample of a compound is made with the exact same elements with the same proportions

Law of Conservation of Mass ; example

Mass is neither created or destroyed in chemical reactions ; 2H₂ + O² → 2H₂O

Law of Multiple Proportions

Compounds always have a whole number ratio of one element to the other by mass

Ex: NO = 1N:1O

NO² = 1N:2O

Dalton’s First Atomic Theory Statement

All matter is composed of atoms

Dalton’s Second Atomic Theory Statement

Atoms of the same element are identical

Dalton’s Third Atomic Theory Statement

Atoms of different elements are all unique in properties

Dalton’s Fourth Atomic Theory Statement

Atoms cannot be subdivided, created, or destroyed

Dalton’s Fifth Atomic Theory Statement

In chemical reactions, atoms are combined, separated, or rearranged

Ions (charged atoms)

Atoms of the same element with different amounts of electrons

Anions

Negatively charged ions with more electrons than protons

Cations

Positively charged ions with more protons than electrons

Average atomic mass definiton ; Equation

The average mass of all the isotopes of the same element ; (Mass)(%) + (Mass)(%)/100

Radioactivity

The spontaneous emission of radiation by the nucleus of unstable isotopes undergoing nuclear decay to become more stable

How does the nucleus of a radioactive isotope attempt to become more stable?

By emitting alpha particles, beta particles, gamma rays, or energy

Non ionizing radiation

Does not affect our DNA

Ionizing radiation

Removes electrons from DNA which breaks our molecules up

Alpha Radiation ; What is it? ; What blocks it?

Weak ionizing radiation ; A gas similar in mass to Helium ; thick plastic, paper

Beta radiation ; What blocks it?

Medium ionizing radiation that turns a neutron into a proton ; wood, aluminum

Gamma radiation ; What is it? ; What blocks it?

High ionizing radiation; Small pure energy; Lead, 3 meters of concrete

Nuclear Fusion ; Where can it occur?

Lighter nuclei are fused together ; Inside stars like the Sun

Nuclear Fission ; Where can it occur?

Heavy nucleus is split into smaller nuclei ; Nuclear power plants

What do both nuclear fusion and fission release?

Energy

What else is released in nuclear fission besides energy?

Neutrons (chain reaction)

The mass of an atom is always _____ than the sum of its _____

less ; subatomic components

Mass Defect

The difference between the sum of the masses of the components and the measured atomic mass

Alpha decay

Nuclear fusion

Nuclear fission

Gamma decay

Change in _____ corresponds to chnage in _____

mass ; energy

What do the letters mean in Einstein’s equation: E=mc²

E = energy ; m = mass ; c² = speed of light (squared because its a huge number)

Who first discovered the phnomenon of Radioactivity?

Henri Bacquerel

Who were the first to use the term Radioactivity?

Pierre Curie and Marie Curie

Electron Capture

Electron from inner orbital is captured by nucleus of atom and combined with a proton to form a neutron

What causes atoms to be radioactive

When ratio of protons and neutrons is unbalanced

When radioactive isotopes decay, they do so _____

exponentially

Half Life

The time it takes for half of a radioactive sample to decay

Mass of Alpha radiation

4 amu

Mass of Beta radiation

.00054 amu

Mass of gamma radiation

0 amu

Gamma ray

Neutron

Beta particle

Alpha particle

Beta particle

Alpha particle

Proton

Positron

What subatomic particles determine the stability of an atom?

Protons and neutrons

Is the Law of Conversion of Mass violated when a gas is formed?

No

What kind of elements will undergo fission or fusion?

Elements lighter than Iron-56 will undergo fusion and heavier will undergo fission

2-1 Lab: Conservation of Mass

1. The individual mass of Sodium Carbonate and Calcium Chloride was equal to the mass of both poured in a beaker, proving the law of conservation of mass.

2. The burning steel wool experiment proved the law of conservation of mass because while burning, the iron in the steel wool reacts with oxygen from the air, forming iron oxide which increases the mass by adding the mass of the oxygen atoms along with the steel wool.

2-2 Skittle Isotopes

Adding up all the weighed masses of isotopes 64-68 of Calorium by the equation (% distribution) x (mass of isotope)/100 helped figure out the average atomic mass of Calorum.

PHET Build An Atom Simulation

Charge: ratio of protons and electrons

Element: # of protons

Mass #: protons + neutrons

Stability: too many/too few neutrons: proton ratio

2-3 Modeling Nuclear Reactions

Big marshmallow = proton

Big marshmallow with little marshmallow on top = neutron

Little mashmallow = beta particle

Radioactive elements emit particles/ energy from their nucleus to become more stable

Lab 2-4 Half Life (How does a graph showing nuclear decay be used to find the half life of a radioactive substance)

How much time does it take for half of the sample to decay

Lab 2-4 Half Life Part 2 (Why do nuclear reactions produce so much energy?)

The strong nuclear force holding protons and neutrons together in the nucleus is significantly stronger than the electromagnetic forces holding electrons in orbit around the nucleus, and during nuclear reactions, all that energy is released.

2-4 Half Life (Part 3) (Can you predict when a single atom will decay?)

No because the decay of a single atom is spontaneous. And just like the lab, to roll any number with a dice is based on probability (random).