Lecture Series 2 Basic Chemistry Vocabulary Flashcards
atom
The smallest unit of an element that retains the element’s distinctive properties. Atoms are the building blocks of all matter.
proton
A subatomic particle, it is the positively charged particle found in the nucleus of an atom.
neutron
A subatomic particle, it is an electrically neutral particle found in the nucleus of an atom.
electron
A subatomic particle, it is a negatively charged particle found outside the nucleus of an atom.
atomic number
The number of protons in an atom’s nucleus.
molecule
an association of atoms held together by nuclear bonds
element
a pure substance that has distinctive physical and chemical properties, and cannot be broken down into other substances by ordinary chemical methods.
ion
an atom that has lost or gained electrons and therefore is either negatively or positively charged
isotope
two or more forms of an element that have the same number of protons but different numbers of neutrons
chemical reaction
the process of breaking existing chemical bonds and creating new ones
chemical bond
a force that holds two atoms together
ionic bond
the chemical attraction between a negatively charged ion and a positively charged ion
covalent bond
the sharing of electrons between two atoms
polar molecule or dipole
a molecule whose electrical charge is shared unevenly, with some regions being electrically negative and others being electrically positive
hydrogen bonding
the weak electrical attraction between a hydrogen atom with a partial positive charge and a neighboring atom with a partial negative charge
pH scale
a logarithmic scale that indicates the concentration of hydrogen ions. The scale goes from 0-14 with 0 representing an extremely high concentration of free H ions and 14 representing the lowest concentration.
hydrophobic
literally “water fearing.” Excluded from water
hydrophilic
literally “water loving.” Soluble in water.
atomic nucleus
the small, dense region consisting of protons and neutrons at the center of an atom
compound
a mixture that is composed of two or more separate elements and contains more than one type of atom bonded together, ex. phytochemicals and buffers
electron shell
the outside part of an atom around the atomic nucleus. It is a group of atomic orbitals with the same value of the principal quantum number n. Electron shells have one or more electron subshells, or sublevels
electron fill order
First electron shell can hold up to 2 e-•2nd electron shell can hold up to 8e-•3rd electron shell can hold up to 18e-•4th electron shell can hold up to 32e-•However, 3rd and 4th shells will not fill with more than 8 electrons until all 18 or 32.
electron frequency
the energy of an electron expressed as light
free radicals
a molecule used within the biochemical pathways of cells that has lost an electron and therefore will steal an electron from the closest molecule; can set off a chain reaction – resulting in cell death and even tissue damage
metallic bond
Electron pooling, the force of attraction between valence electrons and the metal atoms. It is the sharing of many detached electrons between many positive ions, where the electrons act as a “glue” giving the substance a definite structure. It is unlike covalent or ionic bonding
polar covalent bond
a particular type of covalent bond. In a polar covalent bond, the electrons shared by the atoms spend a greater amount of time, on the average, closer to the Oxygen nucleus than the Hydrogen nucleus; When two atoms are bonded and their nucleus contains different numbers of protons
nonpolar covalent bond
a type of chemical bond where two atoms share a pair of electrons with each other. Polar covalent bonding is a type of chemical bond where a pair of electrons is unequally shared between two atoms.
polar molecule (dipole)
a net dipole as a result of the opposing charges (i.e. having partial positive and partial negative charges) from polar bonds arranged asymmetrically. Water (H2O) is an example of a polar molecule since it has a slight positive charge on one side and a slight negative charge on the other.
nonpolar molecule
A molecule may be nonpolar either when there is an equal sharing of electrons between the two atoms of a diatomic molecule or because of the symmetrical arrangement of polar bonds in a more complex molecule.
cohesion
Ability of water molecules to cling to each other due to hydrogen bonding
adhesion
Ability of water molecules to cling to other polar surfaces
pH
Mathematical way to indicate the number of hydrogen ions in solution; pH (potential of hydrogen) is a scale of acidity from 0 to 14. It tells how acidic or alkaline a substance is. More acidic solutions, have lower pH
buffer
a compound that accepts H+ in response to a pH change. Theses chemicals or combination of chemicals keeps pH within normal limits; Resists pH change by taking up excess H+ or OH-; pH of blood is about 7.4 – maintained by buffers – the main one is the bicarbonate ion.
dissociation
the disconnection or separation of something from something else; Water, which not only dissolves many compounds but also dissolves more substances than any other liquid, is considered the universal solvent. A polar molecule with partially-positive and negative charges, it readily dissolves ions and polar molecules; Due to polarity and H-bonding, water dissolves many substances
hydration
a term used to indicate that a substance contains water; When table salt (NaCl) is mixed in water, spheres of hydration form around the ions. Since many biomolecules are either polar or charged, water readily dissolves these hydrophilic compounds.
surface tension
the elastic tendency of a fluid surface which makes it acquire the least surface area possible. … At liquid–air interfaces, surface tension results from the greater attraction of liquid molecules to each other (due to cohesion) than to the molecules in the air (due to adhesion). Water has a high surface tension - Water molecules at the surface cling more tightly to each other than to the air above mainly due to hydrogen bonding
specific heat of water
The specific heat of water is called the calorie (not the same as kilo calories in food), and it is the amount of heat energy needed to raise 1 gram of a substance by 1 degree celsius. Water has a higher specific heat than sand, for example. It takes more heat energy to raise the temperature of water than it does to raise the temperature of sand.
heat capacity
The capability of a substance to absorb heat energy; The many hydrogen bonds linking water molecules allow water to absorb heat without greatly changing its temperature.
heat of vaporization
the amount of energy (enthalpy) that must be added to a liquid substance, to transform a quantity of that substance into a gas; Takes a great deal of energy to break H bonds for evaporation, heat is dispelled as water evaporates
heat of fusion
opposite of heat of vaporization and is the amount of heat energy must withdraw to cause water to freeze or change from liquid to solid.
density
the degree of compactness of a substance
subatomic particle
the three components of an atom, the proton, neutron, and electron
