General Chemistry Stuff Flashcards
Definition of Chemistry
the study of matter and the changes it undergoes
Definition of matter
anything that has mass and takes up space
Definition of atoms
submicroscopic particles that are the fundamental “building blocks” of all matter
Physical characteristics of solid
- definite shape
- not easily compressible
- molecules are densely packed
Physical characteristics of liquid
- no definite shape
- not easily compressible
- molecules are loosely packed
Physical characteristics of gas
- no definite shape
- easily compressible
- molecules not packed
An tank of gas becomes “empty” when -
the pressure inside the tank equalizes with the pressure of the atmosphere (even if there is still gas in the tank)
Atomic mass
Made up of the protons and neutrons
The number of protons gives us it’s___ and identifies which ___ it is
atomic number; element
What does changing the number of neutrons of an element do?
change the mass and creates isotopes
What determines the charge of the element?
The electrons
Definition of a molecule
two or more atoms joined together
Definition of a compound
a molecule that contains at least two different elements
What is matter called that consists of two or more pure substances that retain their individual identities?
a mixture
What is a pure substance that can be broken into separate parts called?
a compound
What are chemical properties of matter?
property displayed by a substance caused by a change in it’s composition (flammability, acidity, toxicity)
Where are alkali metals found?
Group 1
Where are alkaline earth metals found?
Group 2
Where are halogens found?
Group 17
Where are noble gasses found?
Group 18
Where are transition metals found?
Group 3-12
What are core electrons?
innermost electrons that occupy the lowest energy levels and are not involved in chemical bonding
What are valence electrons?
outermost electrons that occupy the highest energy level and are involved in chemical bonding
Aufbau principle
an electron occupies the lowest-energy orbital that can receive it
Trends of atomic size on periodic table
increases going down and to the left
Trends of electronegativity on periodic table
decreases going down and to the left
Empirical formula
the simplest whole number ratio of the elements in a compound
Structural formula
the exact number of each type of element and exact manner in which these atoms are bound together (Lewis structure)
Molecular formula
the exact numbers of each type of element found in a compound
Define atomic elements
elements that exist in nature with single atoms as their basic unit (Na, Mg, Ag, Au)
Define molecular elements
elements that exist in nature as molecules (H2, N2, O2, Cl2, Br2, P4)
What is a molecular compound?
composed of two or more non-metals
Melting
Solid–> liquid
Freezing
Liquid–> solid
Vaporization
Liquid –> gas
condensation
gas–> liquid
deposition
gas–> solid
sublimination
solid–> gas
Atoms
Submicroscopic particles that are the fundamental building blocks of all matter
What makes up the bulk of an atoms mass?
Protons and neutrons
Where are protons, neutrons and electrons located?
Protons and neutrons are in the nucleus.
Electrons reside in the space around atoms (electron cloud)
What is an element?
Cannot be separated into simpler substance
What is a compound?
Substance composed of two or more elements.
Can be separated into simpler substances/elements only by chemical methods
What is a homogeneous mixture?
A mixture with uniform composition (solution)
What is a heterogeneous mixture?
Mixture not uniform and composition and properties
What is a pure substance?
Cannot be broken down further
What is the chemical change?
A change that alters composition
Creating different substances
Who developed the atomic theory?
John Dalton in 1808
Atomic theory
Each element is composed of atoms
All atoms of an element have same mass and other properties that distinguish them from other atoms
Atoms combine in simple whole number ratios to form compounds
Atoms of one element cannot change into atoms of another element
Pauli exclusion principle
No 2 electrons can be the same and must be paired opposite (spin paired)
S-orbital
Holds 2 electrons
P-orbital
3 orbitals
Holds 6 electrons
D orbitals
5 orbitals
Holds 10 electrons
F- orbitals
7 orbitals
holds 14 electrons
Why do atoms gain/lose electrons?
To give electron configuration similar to noble gas (more stable)
Cations
Lose electrons
Cations are smaller than corresponding atoms
Anions
Gain electrons
Anions are bigger than corresponding atoms
Non- metals
Do not conduct electricity
Ex: most gases
Metals
Malleable/ductile
Conduct electricity
Usually solid (except Hg)
Metalloids
Properties of both metals and nonmetals
Neutrons
Isotope- number of protons
Law of conservation of mass
Lavoisier—matter is neither created nor destroyed
matter is converted into other forms not destroyed
Law of definite proportions
All samples of a given compound have the same proportions of their constituent elements
Ex: water (however it got there all water is 2H+ and 1O
Toxicity
An example of chemical property
Law of multiple proportions
When two elements form two different compounds with similar bonding
Masses of element b that combine with the same amount of element A can be expressed as a ratio of small whole number
Example of chemical change
Iron rusting—iron rebinding to O2 changes chemical properties
Diatomic elements
“Have No Fear Of Ice Cold Beer”
H2
N2
F2
O2
I2
Cl2
Br2
Ionic compound
Metal (cation) and nonmetal (anion)
Molecular compounds
2 or more nonmetals
What is Zn ion
Zn2+
What is Ag ion
Always Ag+
What is the only poly atomic cation?
Ammonium NH4+
How to determine ionic charge of transition metal?
Cation charge= -(anion subscript)(anion charge)/ (cation subscript)
Binary acids
HCl: hydrochloric acid
HBr: hydrobromic acid
HI: hydroiodic acid
HF: hydrofluoric acid
Oxoacids
Come from polyatomic ions
-ate goes to -ic
-ite goes to -ous
Reducing chemical formulas
CAN reduce ionic compounds
CANNOT reduce molecular compounds—would change compound
Why do atoms form bonds?
To lower potential energy(more stable)—high energy things are unstable
Bonds allow unpaired electrons to become paired
Polar covalent bond
Electrons not shared equally
Electron density more towards most electronegative atom
Nonpolar covalent bonds
Electrons are shared equally between atoms
Usually when electronegativity is low
Ex: C bonds, 2 of some element bonded together
Exceptions to octet
H: 2 electrons
B: 6 electrons
Al: 6 electrons
Expanded octets
Period 3 or higher
Due to D orbitals
Lone pairs
Lone pairs have greater density than peripheral atoms—repel each other
If octahedral has lone pair which axis is it drawn on
Lone pairs fill axial axis
If trigonal bipyramidal have a lone pair where does it go first?
Equatorial axis fill with lone pairs
Binary ionic
Cation and anion are both one element ex: NaCl
Electronegativity
Property for bonding and reactivity
