Chem110- Unit2

The characteristics of the matter

State and composition classifies ____

Gaseous state, liquid state, and solid state are the 3 states of ____

• A recognizable difference in the appearance of a substance without causing any change in its composition or identity
• Ex-water: snow-rain-humidity

Observed or measured without changing the composition or identity of a substance

Result in change of composition and can be observed only through chemical reactions

• Chemical substance is converted to one or more different substance by rearranging, removing, replacing, or adding atoms.
• Ex: carbon dioxide + water -(light, chlorophyll)-> sugar + oxygen

• (Synonymous w/ chemical reaction)
• Ex: process of formation of sugar

Property of matter that is independent of the quantity of substance

Depends on the quantity of a substance

• Substance with only one component.
• Ex- Pure water:made only of particles containing 2 hydrogen atoms and 1 oxygen atom (H₂O)

A pure substance that cannot be changed into a simpler form of matter by any chemical reaction

Substance resulting from the combination of 2 or more elements in a definite, reproducible way

• Combination of 2 or more pure substances in which each substance retains its own identity.
• Ex: alcohol and water can be combined in a mixture.
• They coexist as pure substances because they do not undergo a chemical reaction.
• Mixture may be homogeneous or heterogeneous.

• Mixture with uniform composition, its particles are well mixed, or thoroughly intermingled.
• Ex: Alcohol and water is described as a solution.

• Mixture with nonuniform composition.
• Ex: Salt and pepper

• Basic structural of an element, which is the smallest unit of an element that retains the chemical properties of that element.
• Made of proton, neutron, and electron.

• Small, dense, positively charged region in the center of the atom.
• Composed of positively charged protons and uncharged neutrons.

Positive charge, in atom's nucleus.

Uncharged, in atom's neucleus

• Negative charged, surrounding the nucleus.
• Low mass compared to protons and neutrons.

Equal to the number of protons in the atom

Equal to the sum of the number of protons and neutrons

• A- mass number: # of protons & neutrons
• Z- atomic number: # of protons
• X- place for atom name
• E- place for charge (+/-)

• Atoms of the same element having different masses because they contain different number of neutrons. (Have different mass numbers)
• Ex: carbon-12 (C-12), carbon-14 (C-14)

• The weighted average of the masses of each isotope that makes up the element.
• Measured in atomic mass unit (amu)
• 1 amu = 1.66 x10^-24 grams (g)

• All matter consists of tiny particles called atoms
• An atom cannot be created, divided, destroyed, or converted to any other type of atom.
• Atoms of a particular element have identical properties
• Atoms of different elements have different properties
• Atoms of different elements combine in simple whole-number ratios to produce compounds (stable combination of atoms)
• Chemical change involves joining, separating, or rearranging atoms

Electrically charged particles resulting from gain or loss of electrons by an atom

• Result of parent atom gaining one or more electrons
• Ex ⁸⁰₃₅Br^-: Bromine-80 gains an electron 

• Result when parent atom lose one or more electrons
• Ex: ³⁹₁₉K⁺: Potassium-39 loses an electron

• Energy level: Orbit level an electron is at, thus fix energy at fix level
• Only allowed location for electrons

• Concept of fix energy and fix levels
• Absorb energy: closer neutron move farther from nucleus
• Release energy: farther neutron move closer to nucleus

Orbit identification number (n)

• 1st step to understanding an atom
• Electrons exist in specific energy states, transition requires specific amount of energy

• Schroedinger's theory.
• Each level has sub level, which also has one or more atomic orbitals

• Designated as n= 1,2,3,...
• 2(n)²
• ex: n=1, 2(1)²= 2, 2 electrons

• ____is a set of energy-equal atomic orbitals within a principal energy level.
• Symbols in order: s<p<d<f
• 1st principal energy level (n=1) has 1 possible levels: 1s
• 2nd principal energy level (n=2) has 2 possible levels: 2s and 2p
• ....
• 4th principal energy level (n=4) has 4 possible levels: 4s, 4p, 4d, 4f

Electron fill the lowest-energy orbital available first

The arrangement of electrons in atomic orbitals

• Bismuth
• Noble gas in bracket: Tin (Sn)1s22s22p63s23p64s23d104p65s24d105p2 krypton; [Kr]5s24d105p2 as shorthand configuration for tin, since [Kr]1s22s22p63s23p64s23d104p6
• Highlight valence electrons