Technical Term of Chemistry (Final Episode)

Continued from episode 2



1)    Element

Ø The alkali metal = The group 1A elements are the most electropositive elements: Li, Na, K, Rb, Cs, Fr.

Ø The alkali earth metal = It is less electropositive and less reactive that the alkali metal: Be, Mg, Ca, Sr, Ba, Ra.

Ø Halogen = It is reactive nonmetals: F, Cl, Br, I, At

2)    Periodic classification of element

Ø Representative element = The elements in group 1A through 7A, all of which have incompletely filled s or p subshells of the highest principal quantum number

Ø Valence electrons = The outermost electrons

Ø Core electrons = All nonvalence electrons in an atom

3)    Atomic vs. Ionic radius

Ø Atomic radius = One – half the distance between the two nuclei in two adjacent metal atoms or in a diatomic molecule

Ø Ionic radius = The radius of a cation or an anion

4)    Ionization energy

Ø Ionization energy (IE) = The minimum energy (in kJ/mol) required to remove an electron from a gaseous atom in its ground state.

5)    Electron affinity

Ø Electron affinity (EA) = The negative of the energy change that occurs when an electron is accepted by an atom in the gaseous state to form an anion.

6)    Lewis dot symbol

Ø Lewis dot symbol = The symbol of an element and one dot for each valence electron in an atom of the element

7)    Bond

Ø Ionic bond = The electrostatic force that holds ions together in an ionic compound

Ø Covalent bond = A bond in which two electrons are shared by two atoms

Ø Lone pair electrons = Pairs of valence electrons that are not involved in covalent bond formation

Ø Octet rule = An atom other than hydrogen tends to form bonds until it is surrounded by eight valence electrons.

Ø Single bond = Two atoms are held together by one electron pair.

Ø Double bond = Two atoms share two pairs of electrons.

Ø Triple bond = Two atoms share 3 pairs of electrons.  

8)    Electronegativity

Ø Electronegativity (EN) = The ability of an atom to attract toward itself the electrons in a chemical bond

9)    Concept of resonance

Ø Resonance = The use of two or more Lewis structures to represent a particular molecule

Ø Lewis structure = A representation of covalent bonding in which shared electron pairs are shown either as lines or as pairs of dots between two atoms, and  lone pairs are shown as pairs of dots on individual atoms.

10)     Dipole moment

Ø Dipole moment (m) = The product of the charge and the distance between the charge.

Ø Polar molecule = Molecules containing atoms of different elements have dipole moments

Ø Nonpolar molecule = They do not have dipole moment.

11)     Hybridization of atomic orbital

Ø Hybrid orbital = Atomic orbitals obtained when two or more noneqivalent orbitals of the same atom combine in preparation for covalent bond formation

Ø Hybridization = The mixing of atomic orbitals in an atom to generate a set of hybrid orbitals e.g. sp-hybridization, sp2-hybridization, sp3-hybridization, sp3d-hybridization, sp3d2-hybridization

12)     Molecular orbital theory

Ø Molecular orbital = The interaction of the atomic orbitals of the bonding atoms and are associated with the entire molecule

Ø Sigma molecular orbital = Electron density is concentrated symmetrically around a line between the 2 nuclei of the bonding atoms.

Ø Pi molecular orbital = Electron density is concentrated above and below a line joining the 2 nuclei of the bonding atoms.

13)     Intermolecular vs. Intramolecular forces

Ø Intermolecular force = Attractive forces between molecules

Ø Intramolecular force = It holds atoms together in a molecule

14)     Properties of liquids

Ø Surface tension = The amount of energy required to stretch or increase the surface of a liquid by a unit area

Ø Cohesion = The intermolecular attraction between like molecules

Ø Adhesion = An attraction between unlike molecules

15)     The rate of reaction

Ø Reaction rate = The change in the concentration of a reactant or a product with time (M/s)

Ø Rate constant = A constant of proportionality between the reaction rate and the concentration of reactant

16)     The rate law

Ø Rate law = The relationship of the rate of the reaction to the rate constant and the concentrations of the reactants raised to some powers

17)     The relation between reactant concentration and time

Ø First – order reaction = A reaction whose rate depends on the reactant concentration raised to the first power

Ø Second – order reaction = A reaction whose rate depends on the concentration of one reactant raised to the second power or on the concentrations of two different reactants, each raised to the first power

18)     Reaction mechanism

Ø Elementary step (Elementary reaction) = A series of simple reactions that represent the progress of the overall reaction at the molecular level

Ø Reaction mechanism = The sequence of elementary steps that leads to product formation

Ø Intermediate = It appears in the mechanism of the reaction but not in the overall balanced equation.

19)     Catalysis

Ø Catalyst = A substance that increases the rate of a reaction by lowering the activation energy

20)     Galvanic cell

Ø Galvanic cell (Voltaic cell) = The experimental apparatus for generating electricity through the use of a spontaneous reaction

Ø Anode = The electrode at which oxidation occurs

Ø Cathode = The electrode at which reduction occurs

Ø Cell voltage (Cell potential) = The voltage across  the electrodes of a galvanic cell

21)     Standard reduction potential

Ø Standard reduction potential = The voltage associated with a reduction reaction at an electrode when all solutes are 1 M and all gases are at 1 atm.

22)     Nuclear binding energy & Natural radioactivity

Ø Nuclear binding energy = The energy required to break up a nucleus into its component protons and neutrons.

Ø Radioactive decay series = A sequence of nuclear reactions that ultimately result in the formation of a stable isotope

23)     Nuclear fission vs. Nuclear fusion

Ø Nuclear fission = The process in which a heavy nucleus (mass number > 200) divides to form smaller nuclei of intermediate mass and one or more neutrons

Ø Nuclear fusion = The combination of small nuclei into larger ones

24)     Earth’s atmosphere

Ø Nitrogen fixation = The conversion of molecule nitrogen into nitrogen compounds

Ø Troposphere = The layer of the atmosphere that contains about 80% of the total mass of air and practically all of the atmosphere’s water vapor

Ø Stratosphere = It consists of nitrogen, oxygen, and ozone.

Ø Mesosphere = It is above the stratosphere.

Ø Thermosphere (ionosphere) = It is the uppermost layer of the atmosphere.

25)     The greenhouse effect

Ø Greenhouse effect = The trapping of heat near Earth’s surface by gases in the atmosphere, particularly carbon dioxide

26)     Conductor vs. Semiconductor vs. Insulator

Ø Conductor = It is capable of conducting electric current.

Ø Semiconductor = It normally are not conductors but will conduct electricity at elevated temperatures or when combined with a small amount of certain other elements.

Ø Insulator = Ineffective conductor of electricity

27)     Structure of coordination number

Ø Stereoisomer = Compounds that are made up of the same types and numbers of atoms bonded together in the same sequence but with different spatial arrangements.

Ø Geometric isomer = Stereoisomer that cannot be interconverted without breaking a chemical bond

Ø Optical isomer = It is nonsuperimposable mirror image.

28)     Hydrocarbon

Ø Hydrocarbon = It is made up of only hydrogen and carbon.

Ø Aliphatic hydrocarbon = It does not contain the benzene group or the benzene ring.

Ø Aromatic hydrocarbon = It contain one or more benzene rings.

29)     Polymer

Ø Polymer = A molecular compound distinguished by a high molar mass, ranging into thousands and millions of grams, and made up of many repeating units.

Ø Monomer = Simple repeating unit

Ø Homopolymer = A polymer made up of only one type of monomer.

Ø Copolymer = a polymer containing two or more different monomers.

30)     Protein

Ø Protein = Polymers of amino acid

Ø Amino acid = A compound that contains at least one amino group (-NH2) and at least one carboxyl group (-COOH).



Chang, R. and Goldsby, K.A. (2014). Chemistry (Eleventh edition). New York: McGraw-Hill Education.

Hornby, A.S. (2010). Oxford Advanced Learner’s Dictionary (Eighth edition). New York: Oxford University Press.