Unit 1: Periodic Table, Matter, Chemical Trends

Question 1

Properties of Metals

Answer 1

Solid at room temperature
Except mercury
Good conductors of heat and electricity
Shiny
Ductile (can be stretched into thin wires)
Malleable (can be pounded into thin sheets)
A chemical property: contact with water results in corrosion

Question 2

Properties of Nonmetals

Answer 2

Many are gases at room temperature (though some may be solid or liquid)
Poor conductors of heat and electricity
Dull
Not ductile or malleable. Solid nonmetals are brittle and break easily

Question 3

Properties of Metalloids

Answer 3

Properties of both metals and nonmetals
Solids
Conducts better than nonmetals but not as good as metals
Shiny or Dull
Ductile & Malleable

Question 4

Physical Properties

Answer 4

State 
Colour 
Texture
Shape
Clarity
Solubility
Temperature
Density
PH level

Question 5

Physical Change

Answer 5

Change in state, size, shape, etc but the substance still stays the same

Question 6

Chemical Change

Answer 6

a reaction, a new substance is formed

Question 7

Chemical Property

Answer 7

Describes what a substance reacts with and the manner in which it reacts; describes what the substance is

Question 8

Evidence of Chemical Change

Answer 8

Heat given off/cooling
Light given off
Precipitation
Bubbles of gas
Colour change
Odour change

Question 9

Qualitative Analysis

Answer 9

The identification of a chemical substance in a sample using physical and chemical properties

Question 10

Quantitative Analysis:

Answer 10

The determination of how much of a given component is present in a sample

Question 11

Isotope

Answer 11

Atoms of the same element with different number of neutrons

Question 12

Radioisotope

Answer 12

Radioactive isotopes have the same chemical properties as stable isotopes of the same element, but they emit radiation, which can be detected.
Radioactive isotopes of an element with an unstable nucleus; it emits radiation as their nucleus decays (radioactive decay)

Question 13

Types of Radiation

Answer 13

Alpha rays
Beta rays
Gamma rays

Question 14

Alpha Rays

Symbol -
Charge -
Speed - 
Penetration in air - 
Effective Barrier - 
Composition -

Answer 14

Symbol - (α)
Charge - Positively charged
Speed - Slow
Penetration in air - A few cm
Effective Barrier - Tissue
Composition - 2 p + 2 n (or helium, check pic)

Question 15

Beta Rays

Symbol -
Charge -
Speed - 
Penetration in air - 
Effective Barrier - 
Composition -

Answer 15

Symbol - (β)
Charge - Negative
Speed - fast
Penetration in air - A few m
Effective Barrier - Aluminum
Composition - 1 e (1 neutron is broken into 1 proton and 1 electron and that electron radiates off the of atom and makes the beta particle)

Question 16

Gamma Rays

Symbol -
Charge -
Speed - 
Penetration in air - 
Effective Barrier - 
Composition -

Answer 16

Symbol - γ
Charge - Neutral
Speed - very fast
Penetration in air - unlimited
Effective Barrier - Lead plate (It can even penetrate through concrete of considerable thickness)
Composition - high-energy electromagnetic waves; Gamma rays are usually accompanied by alpha or beta rays

Question 17

Half-Life

Answer 17

The time required for half of the original number of atoms in a radioactive sample to decay
But from after that, you just half the amount of atoms left

Half life = mass/2time/half-life

Question 18

Uses of Radioisotope

Answer 18

Smoke Detectors
Sterilizing Food and Equipment
Radioactive Dating
Radioactive Tracers
Cancer Treatment

Question 19

How much is one atomic mass (amu) and how much does each subatomic particle weight

Answer 19

1 amu = 1/12 of carbon-12 mass
1 p = 1 amu
1 n = 1 amu
1 e = 0.0005 amu

Question 20

Average Atomic Mass and How To Calculate

Answer 20

Weighted average of all isotopes
AAM = (mass of isotope 1)(% available turned into decimals) + (mass of isotope 2)(% available turned into decimals)
Round to 2 decimal places and always put amu units

Question 21

Periodic Law

Answer 21

The principle that physical and chemical properties of elements occur periodically when arranged by atomic number.
* A table best demonstrates these trends, so that similarities between elements appear in both rows and columns.

Question 22

Periodic Trend

Answer 22

The relationship between atomic structure and physical/chemical properties 
Trends in Periodic Table: 
Atomic Radius
Ionic Radius
Reactivity (metal/non-metal)
Ionization Energy
Electron Affinity
Electronegativity
All of the trends depend on Force of Attraction (Fatt) between the valence electrons and the nucleus
Fatt α Zeff/d^2

Question 23

Atomic Radius

Answer 23

Higher force of attraction between valence electrons and atoms means smaller atomic radius
Lower Fatt means larger atomic radius

Atomic Radius - the radius of an atom
Half the distance between the neighbouring nuclei

measured in picometers (pm)
1pm = 10-12m

Question 24

Effective Nuclear Charge (Zeff) and Number of Shells (d)

Answer 24

Effective Nuclear Charge (Zeff): Describes pull of nucleus on valence electrons (Net proton power)
Zeff = pull of the nucleus – shielding effect of inner electrons
Zeff = [number of protons] – [number of inner electrons]
Ex. Zeff for N is 7 – 2 = 5
*NOTE: Zeff will always equal the number of valence e- in an atom
Number of Shells (d) = period number
Ex. d = 2 for Nitrogen (2 shells)

Question 25

Ionic Radius

Answer 25

The cations are smaller than their parent atoms because they have more protons than electrons, and also have 1 less shell, which increases Fatt.
The anions are larger than their parent atoms because they have a full valence shell and have more electrons than protons, which decreases Fatt.
The more positive an ion is the smaller it is because Fatt increases, while the more negative an ion, the larger it is because Fatt decreases.

Question 26

Reactivity

Answer 26

An element’s ability to combine with other substances to become stable (isoelectronic to a noble gas – full outer shell)

Metals form positive ions by losing their valence electrons to obtain a noble gas configuration.
Their reactivity depends on how easily the metals lose their valence electrons.
Tend to lose e- to become stable
As Zeff ↑, Fatt ↑ (harder to lose e-) so Reactivity ↓
As d ↑, Fatt ↓ (easier to lose e-) so Reactivity ↑

Non-metals form negative ions by gaining valence electrons to obtain a noble gas configuration.
Their reactivity depends on how easily the non metals gain valence electrons.
Tend to gain e- to become stable
As Zeff ↑, Fatt ↑ (easier to gain e-) so Reactivity ↑
As d ↑, Fatt ↓ (harder to gain e-) so Reactivity↓

Question 27

Ionization Energy

Answer 27

The minimum amount of energy required to remove the outermost electron from an atom or ion in the gaseous state.
Abbreviation is IEi, it has units of kJ/mol.
Low I.E. → gives electrons easily
High I.E. → does not give electrons easily
H (g) —-→ H + (g) + 1 e

Ionization energy goes higher as you go up a group on the periodic table and higher as you go right. (toward Fluorine basically)

Why does Ionization energy decreases down a group?
Fatt - weaker
less energy is required to remove an electron. I.E decreases.

Why does Ionization energy increases across a period?
Fatt - Increases
More energy is required to remove an electron (I.E increases)
Metals require lowest ionization energy because they have only 1-3 valence electrons, noble gases require most because of full valence shell

Question 28

Electron Affinity

Answer 28

Energy change that occurs when an electron is added to an atom in the gaseous state.
UNITS: KJ/mol
Values are generally negative because energy is released.

Higher the negative number greater the electron affinity. I.e. easier for the element to gain an electron.
Think about it as an absolute value without the - to make it easier
The higher the number, the greater the electron affinity

Question 29

Electronegativity

Answer 29

A measure of an atom’s ability to attract electrons into a chemical bond.
Pauling scale Fluorine 4.0 (most electronegative) - Francium 0.7 (least electronegative)