AP 1 Chapter 2

What are Subatomic Particles

Protons, Neutrons, and Electrons

What are Molecules

• A molecule is a group of two or more atoms bonded together that form the smallest identifiable unit of a pure substance.

• Chemical structure consisting of atoms held together by shared electrons

• Ex: H20, O2, CO2

What is a Compound

• Chemical substance made up of atoms of two or more different elements in a fixed proportion regardless if electrons are being shared.

What are Macromolecules

Macromolecules are very large molecules made by joining smaller sub-units together

What is Chemistry

Chemistry is the science that deals with the structure of matter:

• Structure of Atoms

• Basic Chemical Building Blocks

• How atoms combine to form increasingly complex structures

What is Matter

• Anything that takes up space and has mass.

• Made up of atoms. Atoms join together to form chemicals with different characteristics

• Chemical characteristics determine physiology at molecular and cellular levels

What is a Proton

• A subatomic particle with these characteristics:

  • Positive Charge

  • Located in the Nucleus

    • 1 Atomic Mass Unit (amu)

What is a Neutron

• A subatomic particle with these characteristics:

  • Neutral Charge

  • Located in the nucleus

  • 1 Atomic Mass Unit (amu)

What is a Electron

• A subatomic particle with these characteristics:

  • Negative Charge

  • Low Mass (1/1836 amu)

  • Located in the electron cloud outside the nucleus.

  • Electrons bounce around the electron cloud

  • The outer most shell of the atom is called the Valence Shell.

Characteristics of an Atom:

• In a neutral atom, the number of protons equals the number of electrons

• Nucleus:

  • Contains protons and neutrons

  • The number of protons determine the atomic number

  • Atomic number is the number in the lower left-hand corner of periodic table

• Atomic Mass Number:

  • Protons and Neutrons have 1 amu and they determine the mass of the entire atom.

  • It is possible to have more neutrons than protons in an atom

  • Don’t really count the weight of electrons because they weight very little.

• Electron Cloud:

  • Spherical area that contains electrons

  • Electron shell is a 2D way of showing electron cloud

Symbol for Oxygen

O

Symbol for Carbon

C

Symbol for Hydrogen

H

Symbol for Nitrogen

N

Symbol for Calcium

Ca

Symbol for Phosphorus

P

Symbol for Potassium

K

Symbol for Sodium

Na

Symbol for Chlorine

Cl

Symbol for Magnesium

Mg

Symbol for Sulfur

S

Symbol for Iron

Fe

Symbol for Iodine

I

Symbol for Silicon

Si

Symbol for Fluorine

F

Symbol for Copper

Cu

Symbol for Manganese

Mn

Symbol for Zinc

Zn

Symbol for Selenium

Se

Symbol for Cobalt

Co

Symbol for Molybdenum

Mo

Symbol for Cadmium

Cd

Symbol for Chromium

Cr

Symbol for Tin

Sn

Symbol for Aluminum

Al

Symbol for Boron

B

Symbol for Vanadium

V

What is an element

An element is a pure substance composed of atoms of one kind

• The atomic number (number of protons) determines it chemical properties

• Each element contains a different atomic number

• Atoms are identified by protons and interacted with by electrons

What are Isotopes

• An isotope is a variant of a chemical element that has the same number of protons but a different number of neutrons in its nucleus

• Are versions of elements based on mass number

• Mass Number = Number of protons + Number of Neutrons

• Can only have different number of neutrons because if you change number of protons, it changes the element

What are Radioisotopes and what are they used for

• They are isotopes that releases radiation

• They are radioisotopes because they are unstable since they either have too many neutrons or too little

• Weak radioisotopes are used for diagnostic imaging.

What does a hydrogen atom with one neutron called

Deuterium

• Has one neutron and one proton in hydrogen atom

What does a hydrogen atom with two neutron called

Tritium

• Has two neutron and one proton in hydrogen atom

Properties of Electron and Energy Levels

• Electron in the electron cloud determines reactivity of an atom

• Energy levels:

  • Electron cloud contain shells, or energy levels, that can hold a limited number of electrons

  • Lower shell is filled first

    • 1st Shell = 2 Max

    • 2nd Shell = 8 Max

    • 3rd Shell = 18 Max

  • Valence shell: the outermost shell determines the bonding.

    • Atoms wants to fill their outer most shell. They either do that by losing or gaining an electron. They are also share electron.

What is Chemical Notation

• Used to describe chemical compounds and chemical reactions in the body

• Used to describe:

  • Atoms

    • Number in front means not bonded and they are just separate atoms

      • Ex: 2H = Two Hydrogen Atoms not bonded are present

  • Molecules:

    • Number in subscript means there is a bond

      • Ex: H₂ = Two hydrogen atoms bonded together

      • Ex: H₂O = Two Hydrogen atoms bonded with oxygen atom

  • Chemical reactions:

    • The left side of reaction is called reactants

    • The right side is called the product/s

    • Arrow indicate direction of reaction

      • Ex: 2H + O = H₂O

  • Ions:

    • A superscript of (+) or (-) indicates an ion.

    • (+) = Cation

    • (-) = Anion

      • Ex: Na⁺

      • Ex: Ca²⁺

      • Ex: Cl^-

What is Cation

An atom that has lost one or more electrons and has a positive charge

(+)

What is Anion

An atom that has gained one or more electrons and has a negative charge

(-)

What are the three types of chemical bonds

1. Ionic Bonds: Gaining/Losing Electrons

2. Covalent Bonds: Sharing Electrons (Strong Bonds)

3. Hydrogen Bonds: Weak Bonds through attraction from partial charged positive or negative atoms.

What are Ionic Bonds

• An ion is an atom what an electric charge. This is due to atom losing/gaining an electron

• One atom - Electron donor - loses one or more electrons and becomes a cation (+) charge

• Another atom - Electron recipient - gains those same electrons and becomes a anion (-) charge

Ionic Bonds are attractions between cations (positive ions) and anions (negative ions)

What are Covalent Bonds

• When atoms complete their valence shell by sharing electrons with other atoms

• Covalent Bonds are strong bonds

• One electron is donated by each atom to make the pair of electrons

  • Single Covalent Bond: Sharing of one pair of electrons (single dash)

  • Double Covalent Bond: Sharing of two pairs of electrons (double dash)

  • Triple Covalent Bond: Sharing of three pairs of electrons (triple dash)

What is Nonpolar Covalent Bonds

• Equal sharing of electrons between atoms that have equal pull on electrons

What is Polar Covalent Bonds

• Unequal sharing of electrons because one atom has a disproportionately stronger pull than the other atom on the electrons

• Form Polar Molecules

  • Ex: H₂O

  • Ex: HCl

  • Ex: NH₃

• Polar Covalent bonds all have slightly different charges

  • Ex: H2O - The oxygen has a greater Electronegativity (pull/attraction) than Hydrogen. This means that the electron from hydrogen spends way more time with Oxygen atom creating a slight negative charge on oxygen atom and slight positive charge on hydrogen.

What is Hydrogen bonds

• They are weak polar bonds between adjacent molecules (not atoms) based on electrical attractions.

• Involves attractions between a slight positive charge and a slight negative charge

• Hydrogen bonds do not form molecules

• Hydrogen bonds between H₂O molecules cause surface tension

• They bonds are not created, it is simply attractions.

What are the States of Matter and their properties

1. Solid: Constant volume and shape

2. Liquid: Constant volume but changes shape

3. Gas: Changes volume and shape