Exam One Flashcards
Element
A substance that cannot be broken down to other substances by chemical reactions
Matter
Anything that takes up space and has mass; made up of elements
Compound
A substance consisting of two or more elements in a fixed ratio
Atom
The smallest unit of matter that still retains the properties of an element
Subatomic particles
What atoms are composed of
Neutrons
No electrical charge
Protons
Positive charge
Electrons
Negative charge
Atomic number
Number of protons in the nucleus
Mass number
The sum of the protons plus the neutrons in the nucleus
Isotopes
Two atoms of an element that differ in number of neutrons (same number of protons)
Orbital
The three dimensional space where an electron is found 90% of the time
Energy
The capacity to cause change
Potential energy
The energy that matter has because of its location or structure
Electron shell
An electron’s state of potential energy (energy level)
Groups
Elements in a vertical column that have the same number of electrons in their valence shell and thus have similar properties
Periods
Each horizontal row contains elements with the same number of electron shells, ordered by increasing atomic number
Valence electrons
Electrons in the outermost shell
Covalent bond
The sharing of a pair of valence electrons by two atoms, the shared electrons count as part of each atom’s valence shell
Single covalent bond
The sharing of one pair of valence electrons
Double covalent bond
The sharing of two pairs of valence electrons
Electronegativity
An atom’s attraction for the electrons in a covalent bond
Non polar covalent bond
The atoms share the electron equally
Polar covalent bond
One atom is more electronegative, and the atoms don’t share the electron equally
Ionic bonds
Atoms strip electrons from their bonding partners, both atoms are charged
Cation
+
Anion
-
Hydrogen bonds
Form when a hydrogen atom covalently bonded to one electronegative atom is also attracted to another electronegative atom
Ionization energy
Amount of energy required to remove an electron from an atom
Electron affinity
Amount of energy released when an electron is added to form a negative ion
