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Chemistry – PSSA Review – Presentation. Chemistry – PSSA Review. S11.C.1 – Structure, Properties, and Interaction of Matter and Energy. Atoms and subatomic particles. PSSA Eligible Content S11.C.1.1.1. Matter. Anything that has mass and takes up space is known as MATTER .

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Chemistry pssa review

Chemistry – PSSA Review

S11.C.1 – Structure, Properties, and Interaction of Matter and Energy

Atoms and subatomic particles

Atoms and subatomic particles

PSSA Eligible Content



  • Anything that has mass and takes up space is known as MATTER.

  • There are two kinds of matter:

    • Pure Substances – Cannot be broken down

      • Elements

        • Examples would include: Fe, Ni, Zn, Hg, Pb, Na, O, He

      • Compounds

        • Examples would include: Water, Carbon dioxide, Sugar

    • Mixtures – Blend of two or more simpler substances

      • Heterogeneous Mixture - each substance retains own properties

        • Examples: Pepperoni Pizza, Chocolate Chip Cookies

      • Homogenous Mixture – uniform composition

        • Examples: Air, Salt water

Parts of the atom
Parts of the Atom

  • ATOM – the basic building block of matter

    • Composed of smaller subatomic particles:

Parts of the atom1
Parts of the Atom

  • NUCLEUS – Center of atom; contains protons and neutrons

  • ELECTRON CLOUD – Space outside of nucleus; Contain electrons

    • Organized into different energy levels at different distances from the nucleus. Most atoms have more than one energy level.

Structure of the atom
Structure of the Atom

  • ATOMIC NUMBER – The number of protons in the nucleus of an atom; No two atoms have the same atomic number!

  • MASS NUMBER – The number of protons plus the number of neutrons in the nucleus of an atom

  • ISOTOPES – Atoms of the same element with different numbers of neutrons; Same atomic number but different mass numbers!!

Basic layout students do not have this slide
Basic Layout (students do not have this slide)

7 rows = “periods”

18 columns = “groups”

Chemistry pssa review presentation

  • NEUTRAL ATOM – Number of electrons = number of protons (positive = negative)

    • Valence Electrons – electrons located in the outermost energy level

  • ION – Atom that has a charge (has either lost or gained electrons during a reaction)

    • Cation – Positively charged ion (lost electron(s))

    • Anion – Negatively charged ion (gained electron(s))

Properties of matter
Properties of Matter

  • Physical

    • characteristics of matter that can be observed or measured without changing the identity of the substance.

      • Ex: Color, texture, phase, malleability, ductility, density, melting point, boiling point

  • Chemical

    • Characteristics of matter that describe how substances change in chemical composition.

      • Ex: flammability, corrosion, decomposition, digestion, respiration

Mass volume density
Mass, Volume, Density

  • Mass

    • Amount of matter present in a sample of a substance

    • Metric base unit = Gram, g

  • Volume

    • Amount of space occupied by a substance

    • Metric base unit = Liter, L

  • Density

    • Ratio of mass to volume of a substance

    • D = mass


Molecular shapes
Molecular Shapes

  • Nonpolar

    • Even distribution of electrical charge

  • Polar

    • Uneven distribution of electrical charge

    • Dipole (d+, d-)

Effects of molecular shape
Effects of Molecular Shape

  • Nonpolar

    • Weak attractive forces

    • Low melting and boiling points

  • Polar

    • Strong attractive forces

    • High melting and boiling points

Key ideas
Key Ideas

  • COMPOUND – Two or more elements combine chemically

    • Important characteristics:

      • Have definite composition

      • Can be broken down into simpler substances by chemical means

      • Properties of the compound differ from the properties of the individual elements making it up!

Electrons and bonding
Electrons and Bonding

  • Electrons

    • Negatively charged particles

    • Located in energy levels

      • Those closest to the nucleus have the smallest amount of energy

  • ELECTRON CONFIGURATION – Arrangement of electrons around the nucleus of an atom

    • Each energy level can hold a specific amount of electrons:

Electrons and bonding1
Electrons and bonding

  • Valence electrons are lost, gained, or shared when atoms react with each other to form bonds

  • CHEMICAL BONDS – forces that hold atoms together

    • Three types:




Ionic bonds
Ionic Bonds

  • IONIC BOND – Formed from transfer of electrons from a positively charged ion to a negatively charged ion

    • OCTET – Atoms seek to have 8 electrons in their outer most level

Covalent bonds
Covalent Bonds

  • COVALENT BOND – Formed when two atoms share electrons

    • OCTET – Seek to have 8 electrons in outer most level

    • MOLECULE – Structure formed through covalent bonding

    • LEWIS STRUCTURE – Visually shows covalent bonding and how electrons are shared

Metallic bonding
Metallic Bonding

  • METALLIC BOND – Formed when two metals combine

    • Electron Sea – Group of loosely bound electrons that are shared by all metal cations (+ charged ions)

The periodic table

The Periodic Table


Basic layout
Basic Layout

7 rows = “periods”

18 columns = “groups”

Properties of elements
Properties of Elements

  • Metals

    • Solid (except Hg), lustrous, malleable, ductile, good conductors of heat and electricity, tend to lose electrons in chemical reactions

    • On the left of the steps (except Hydrogen)

  • Nonmetals

    • Most are gases, dull color or colorless, brittle when in the solid phase, poor conductors of heat and electricity, tend to gain electrons in chemical reactions

    • On the right of the steps

  • Metalloids

    • Blended properties of metals and nonmetals

    • On the steps

Special groups
Special Groups

Group 1 = Alkali Metals Group 17 = Halogens

Group 2 = Alkaline Earth Metals Group 18 = Noble Gases

Groups 3-12 = Transition Metals

Properties of elements slide 2
Properties of Elements (Slide 2)

  • Alkali Metals

    • React vigorously with nonmetals and water

    • Require special storage

    • Have 1 valence electron; form +1 ions

  • Alkaline Earth Metals

    • Not as reactive as group 1 metals

    • Have 2 valence electron; form +2 ions

  • Transition Metals

    • Hard solids with high melting points

    • Form colorful ions of varying charge

Chemistry pssa review presentation

  • Halogens

    • Most reactive nonmetals

    • 7 valence electrons, -1 ions

  • Noble Gases

    • Least reactive of all elements

    • 8 valence electrons = “Octet”

Gases and gas laws

Gases and gas laws


Kinetic molecular theory
Kinetic Molecular Theory


  • No definite shape

  • No definite volume

  • Molecules are very fart apart

  • Elastic collisions

  • Weak intermolecular attraction

  • Greatly affected by changes in :

    • Temperature – average kinetic energy of molecules; measured in KELVIN

    • Pressure – force exerted per unit area; measured in atm, mmHg, kPa

Charles law
Charles Law

  • V1 = V2

    T1 T2

  • T and V are directly proportional.

Boyle s law
Boyle’s Law

  • P1V1 = P2V2

  • P and V are inversely proportional

Ideal gas law
Ideal Gas Law

Relates P,V, and T to the number of moles (n) of gas

R = 0.08206 Latm/molK

n = number of moles = mass/molar mass

Density of gases
Density of Gases

Affected by changes in volume

d = mass


If V increases, density will decrease.

If V decreases, density will increase.

Reaction rates

Reaction Rates


Chemical reactions
Chemical Reactions

  • Chemical Reaction – One or more substance react to produce new, different substances

    • Reactants  Products

  • 4 types of chemical reactions:

    • Synthesis

    • Decomposition

    • Single Replacement

    • Double Replacement

  • Summary of reactions
    Summary of Reactions

    ** - Activity Series Required!!

    Rate of reaction
    Rate of Reaction

    • RATE OF REACTION – How fast a reaction takes place

      • Affected by:

        • Concentration

        • Pressure

        • Temperature

        • Catalyst

          • CATALYST – Substance that speeds up a reaction, but it itself is not consumed

    Factors affecting rates of reaction1
    Factors Affecting Rates of Reaction

    • Temperature – Measure of average kinetic energy in a substance

      • Increase temperature = Increased rate of reaction

    • Pressure – Force exerted on a unit area of surface

      • Little affect on solids, liquids

      • Increase Pressure = Increased rate of reaction

    • Concentration – Amount of molecules present per unit volume

      • Increased Concentration = Increased rate of reaction

    • Catalyst – Substance that increases rate without being permanently changed or used up

    Factors affecting rates of reaction2
    Factors Affecting Rates of Reaction

    • EQUILIBRIUM – Stable condition in which opposing forces cancel out

    • REVERSIBLE REACTION – Reactions that can occur in both the forward and reverse directions

    • LeChatlier’s Principle – Chemical reactions will “work” to relieve changes made to it and get (shift) back into equilibrium

      • Add more of a substance – shift away from added

      • Remove substance – shift towards removed

      • Decrease volume – shift toward side with fewer gas

    Chemistry pssa review1

    Chemistry – PSSA Review

    S11.C.2 – Energy Sources and Transformation of Energy, or Conversion of Energy

    Chemical reactions energy diagrams
    Chemical Reactions -Energy Diagrams

    Endothermic Reactions – Require energy (energy is a reactant)

    Products are at a HIGHER energy than the reactants

    Chemistry pssa review presentation

    Exothermic Reactions – Release energy (energy is a product)

    Products are at a LOWER energy than the reactants

    Bond changes
    BOND CHANGES product)

    • Breaking bonds is always an ENDOTHERMIC process

    • Making bonds is always an EXOTHERMIC process

    Physical changes
    Physical Changes product)

    • Change of STATE

    Heating Curve

    Cooling Curve