2.2 Chemistry Flashcards
Chemistry
Study of matter
Matter
Composed of elements
Elements
Specific substance that can’t be broken down into simpler substances by chemical reactions
Number of elements, naturally occurring, unstable
118, 94, 24
Unstable elements
Don’t exist for very long and some can only be produced in extreme conditions such as in nuclear reactions or in particle accelerators
Periodic table
First created by Dmitri Mendeleev. Includes important info about each of the elements and how they relate to one another
Atom
Smallest component of an element that retains all of the chemical properties of that element
Nucleus (chemistry)
Central region of an atom containing protons and neutrons in all elements heavier than hydrogen
Protons
Positively charged particles found in the nucleus of an atom
Atoms have the same number of electrons and protons
Neutrons
Particles with a mass but no charge found in the nucleus of all atoms heavier than hydrogen
The “glue” holding all of the protons in the nucleus of an atom
Electrons
Negatively charged particles scattered around the nucleus of an atom
Atoms have the same number of electrons and protons
Valance electrons
Found on outer electron shell of an atom and important for chemical reactions
Atomic number
Number of protons
Mass of an atom
Approximately equal to mass of protons and neutrons since electrons are about 1837 times smaller than protons
Electric charge
Play a role in determining how electricity moves through a material
Orbitals
Regions around the nucleus where there is a high probability of finding electrons
Not necessarily circular
Electron subshells
S – spherical
P – 3 dumbbell shaped
D – 5 more complex
F - 7 more complex
First electron shell
1 s-orbital that can hold 2 electrons
Second electron shell
1 s-orbital and 3 p-orbitals, each hold 2 electrons for a total of 8 electrons
Significance of row on periodic table
The row an element is placed indicates how many electron shells it contains
Inert elements
Don’t react with other elements because they have full outer shell
Compound
Different physical and chemical properties than the elements from which it’s made
Isotopes
Elements that have same number of protons and electrons but different number of neutrons
Chemically identical but many have different stabilities
Some are radioactive
Ionic bonds
Transfer of electrons between two atoms that creates a negative ion and positive ion with full outer shells.
Ion
Atom with a charge
Anion
Ion with negative charge
Cation
Ion with a positive charge
Covalent bonds
Elements share electrons to achieve a full outer shell (rather than gaining/losing electrons)
Single, double, or triple
Molecules
Resulting product of a covalent bond
Smallest unit of a compound that had the same properties as the compound but not always a compound
Don’t have to contain more than one element
Compound
Result of bond between at least two different elements
Nonpolar covalent bonds
Covalently bonded atoms that share electrons nearly equally
Polar covalent bonds
Covalently bonded atoms that share electrons unequally due to a difference in electronegativity or charge
Acid
Increases the concentration of hydrogen ions in a solution (low pH)
Base
Provides hydroxide ions or other negatively charged ions that combine with hydrogen ions (high pH)
pH
-log[H+]
A pH difference of 1 indicates a 10x difference in hydrogen ions
Indicates acidity or alkalinity
<7 acidic
7 neutral
>7 basic (alkaline)
Octet
Full outer orbital
Dipole
Created when a molecule has regions of charge that are separated
Hydrogen bonds
Form between the partial positive charge on the hydrogen of one water molecule and the partial negative charge on the oxygen of another water molecule
Dipole
Separated regions of charge on a molecule
Universal solvent
Water, ions of an ionic molecule are more attracted to the water than to each other so they break apart and dissolve
Cohesion
Attraction of a molecule to itself
Adhesion
A molecule’s attraction to other substances
