S1 Unit 3 chemistry terms

crop diversity

The variance and genetic characteristics of plants used in agriculture

cross breeding

Combining different varieties of animals or plants to produce new traits.

food engineering

an engineering field that combines chemistry, biology, microbiology, and other branches of science to produce food. If focuses on food preservation and distribution to meet society’s demands.

genetic engineering

the science of altering the structure of genetic material in a living organism

organic

of or relating to a living or once living organism; based on the element carbon

pesticides

Chemicals that are used to kill plants and animals that are harmful to agriculture.

atomic radius

A measure of the size of an atom. The atomic radius is the length from the center of an atom to the atoms outer edge.

d orbitals

Cloverleaf shaped orbitals where electrons can be found

electron configuration

A method of writing arrangement of electrons in an atom

Electronegativity

Tendency of an atom in a molecule to attract shared bonding electrons.

electron orbit shell

A pathway on which negatively charged electron particles continuously circle the nucleus of an atom

Energy level

amount of energy an electron has, which also indicates the position of an electron in an atom

Energy sublevel

An energy level within the electron shell. Each sublevel is assigned a letter. ex 3p energy sublevel

first ionization energy

The amount of energy required to remove the atoms electron from an atom or molecule

Ionic radius

A radius of an atom in an ionic state

Noble gas configuration

the electron structure of an atom in which the outer electron shell contains eight electrons

orbital

A space around an atom that can contain up to two electrons. Different types of orbitals have different shapes.

P orbital

A dumbbell shaped orbital where electrons can be found

periodic trend

Patterns in the properties of elements based on where elements are on the periodic table

Reactivity

The tendency of a substance to undergo chemical reaction.

S orbital

a spherically shaped or orbital where electrons can be found

shielding

An effect in which core electron screens the valence electrons from the positive charge in the nucleus.

anion

A negatively charged ion

cation

A positively charged ion

Chemical bond

an attraction between atoms

Chemical formula

The representation of a compound or molecule using symbols and numbers to indicate the type and number of atoms present. The chemical formula for water is H2O.

covalent bond

a type of bond in which electrons are shared between atoms.

dipole dipole forces

Intermolecular attractive forces between the negative end of one polar molecule and the positive end of another polar molecule

dipole moment

A measure of the degree of separation of charge in a polar molecule

Double bond

A covalent bond in which two electron pairs are shared between two atoms.

electron dot diagram

A diagram using dots to represent valence electrons on an atom

Hydrogen bonding

A type of dipole-dipole force occurring between a hydrogen atom and a highly electronegative atom such as nitrogen, oxygen or fluorine

ionic bond

an attraction between positively and negatively charged ions

intermolecular force

An attractive or a repulsive force between molecules

Intramolecular forces

Attractions that exist within a molecule

Lewis structure

A sketch of a molecule that uses dots to represent valence electrons

Metallic bond

A type of bond in which electrons move freely among the positively charged ions of metals

Nonpolar

Having no charge

Non-polar covalent bond

A type of bond in which electrons are shared equally by both atoms

octet rule

The observation the atoms are most stable when they’re surrounded by eight electrons in the outer shell

Polar

Having an unbalanced arrangement of charge

Polar covalent bond

A bond in which electrons are unevenly shared between atoms

Single bond

A covalent bond consisting of a single pair of shared electrons

Triple bond

A covalent bond involving the sharing of three pairs of electrons

Van der Waal’s forces

Weak intermolecular attractions or repulsions

bent

The shape of a molecule having a central atom bonded to two other atoms and having two lone pairs of electrons.

covalent compound

A substance composed of cations and anions held together by covalent bonds

Ionic compound

A substance composed of cations and anions held together by ionic bonds

lone pair

A pair of electrons that is not in a chemical bond on an atom

oxidation state

The charge an atom would have if it gained or lost electrons; The most likely oxidation state for an atom is the charge it would have if it gained or lost electrons to get a full octet

polyatomic ion

An ion that is composed of more than one kind of atom

prefixes

Letters, words or numbers used at the beginning of a word or to or change a certain meaning. Milli- is the prefix in the word millimeter. 1 mm means that something is 1000th of a meter in length

stable

Not likely to change

tetrahedral

An object that is shaped like a pyramid with four triangular sides (three of which slope in and join together at a point).

Trigonal planar

The shape of a molecule with one atom at the center bonded to three atoms of the corners of a triangle. It exists in one plane.

trigonal pyramidal

describing a molecule that has the shape of a pyramid with a triangular base; formed by a central atom bonded to three other atoms and having one lone pair of electrons.

VSEPR

an acronym for valence shell electron-pair repulsion theory, which is used to predict the structure of individual molecules.