Unit 3, Honors Chem

What idea did Democritus introduce regarding matter?

Atoms are the smallest form of matter (cannot be broken into smaller pieces)

What was Dalton’s Theory nicknamed?

“Billiard Ball Model”

What are the three tenets to Dalton’s Theory?

1. Atoms make all matter and cannot be created nor distroyed

2. All atoms of the same element are identical and separate from atoms of differing elements

3. Atoms form compounds with consistent ratios

What did Dalton believe atoms to look like? What’s wrong with this?

Each atom was a microscopic ball that had a fixed number of holes where other elements could join to form compounds. His model was too simple and didn’t show anything regarding subatomic particles

Who first considered the existence of electrons?

Thomson

Explain Thomson’s “Cathode Ray Experiment” and what it did

Voltage was applied to a sealed glass tube with little air inside, causing a particle beam to flow through from the cathode. It was used to test particle properties. The particles were repelled from the negatively charged plates (cathode rays were negatively charged and small, the experiment also aided in finding mass-to-charge ratio.

What was the nickname for Thomson’s model?

“Plum Pudding Model”

What did Thomson think an atom looked like?

Similar to a chocolate chip or kitchen sink cookie, he imagined a sphere littered with various subatomic particles randomly throughout

Who discovered the nucleus?

Rutherford

Explain Rutherford’s “Gold Foil Experiment” and what it did

A sheet of pure gold was made the target of a stream of Alpha Particles, and the stream was expected to go directly through due to Thomson’s atomic model making in seem as if positive charges were spread out. This did not happen, and some particles were deflected, showing the presence of a condensed centers of atoms (the nucleus)

What is Rutherford’s atomic model nicknamed?

“Nuclear Model” (planetary model)

How did Rutherford imagine an atom?

A positively-charged core with negatively-charged electrons surrounding (think basic science logo atom)

Define quantized

Only certain values are allowed

Where did Bohr’s model stem from?

Planetary (nuclear) model

How did Bohr quantize his model?

Only set numbers of electrons can exist on each orbital or electron shell (and none in between)

What was wrong with Bohr’s model?

For smaller atoms it works (like H and He) for more complex models it doesn’t

What did Schrödinger use to explain the behavior of electrons?

A postulate to act like both particles and waves

What is an orbital?

Area around an atom where there is a 90% likelihood of finding an electron, electron cloud/shell

What is the home of electrons known as in the quantum mechanical model (not orbital)?

Electron cloud

What are the types of nuclear changes?

Alpha, Beta, Gamma

What is the mass of a proton?

1amu (atomic mass unit)

What is a proton’s charge?

Positive

Where is a proton found?

In the nucleus

What is the mass of a neutron?

1amu (atomic mass unit)

What is a neutron’s charge?

Neutral

Where are neutrons found?

Nucleus

What is the mass of a electron

N/A (too small to matter)

What is the charge of an electron

Negative

Where can you find electrons?

Orbitals/electron cloud

What is Alpha Decay?

An Alpha Particle (two protons, two neutrons/ one helium) is released from the nucleus to stabilize an element

What is Beta Decay?

A Beta particle (an electron) is emitted from the nucleus because a neutron is converted to a proton and extra negative charge is ejected

What is Gamma radiation?

Extra energy is emitted, doesn’t really effect much

Where is the Atomic Number (Z) found on the periodic table?

Top of element’s box

Where is the Atomic Mass found on the periodic table?

Below the element’s name/symbol

What does the Atomic Number represent?

Number of protons in the nucleus

What makes up the Atomic Mass

Number of protons (1amu) + Number of neutrons (1amu)

What is an isotope?

A variation of an element with a different number of neutrons

How are isotopes named?

Element name or symbol-mass (ex: Carbon-14 or C-14)

What does nuclear notation look like?

A over Z, X (A=atomic mass, z=atomic number, X=element symbol)

How do you calculate Atomic Mass

Atomic Mass= Isotope mass x Fractional abundance

What is a valence electron?

The outermost electron(s) with the most energy

Explain the octet rule

Elements with more than one electron shell form bonds to have eight valance electrons

What is an ion

A charged atom

What is the name for a positively- charged ion?

Cation

What is the name for a negatively charged ion?

Anion

How do you notate Alpha Decay?

[all nuclear notation] (Original element) → (Helium) + (New element with four less amu and two less protons from original)

How do you notate Beta Decay

[All in nuclear notation] (Original element) → (Beta particle) + (New element with one more proton from original)

Where are Metals found on the Periodic Table?

On the left hand side from the “staircase” of metaliods (B- At) Al and Po are also metals

Where are metalloids found of the periodic table

“Staircase” from B-At

Where are Non-Metals found

Right hand side of “Staircase” of metalloids (B-At)

What are properties of Metals?

Lustrous, conductive, malleable, ductile, and some are magnetic and react with acid

What are properties of non-metals?

Dull, brittle, insulator

What is the law of conservation of matter?

Matter cannot be created nor destroyed

What is the Law of definite proportions?

All compounds have fixed ratios (ex: water will always be H2O with a 2.0 or 2:1 Hydrogen to oxygen ratio)

What is the Law of Multiple Proportions?

When multiple compounds are made of the same elements in different proportions the mass of one element that can combine with 1g of the other can be expressed in fixed ratios of small whole numbers

What is a metalloid?

An element that shares traits with both metals and non-metals