Chemistry of Living Things Flashcards
The smallest unit in which an element may be divided while retaining all of the characteristics properties of that element.
Atoms
Anything that has mass and takes up space.
Matter
Unique substances that cannot be broken down in simpler ones by chemical methods.
Elements
What are the colors that correspond to hydrogen, carbon, nitrogen, and oxygen?
Hydrogen: White; Carbon: Black; Nitrogen: Blue; Oxygen: Red.
Number of what = number of what?
Protons and Electrons
Number of protons within the nucleus of an atom.
Atomic Number
The sum of the masses of its protons and neutrons.
Mass Number
All known elements have two or more variants that have the same atomic number but different mass numbers.
Isotopes
Average of the all the relative weights (mass numbers) of all the isotopes of an element, taking in account their relative abundance.
Atomic Weight
Exhibit radioactivity, disintegration of a nucleus like a tiny explosion. The glue that holds quarks smaller particles of protons and neutrons together is less effective in heavier isotopes.
Radioisotopes
A combination of two or more atoms held together by chemical bonds.
Molecule
two or more different elements bind to form molecules of a compound.
Compound
Space occupied by electrons surrounds nucleus of atoms.
Electron Shells
Except for shell 1 elements are stable when they have 8 electrons in their valence shell.
Rule of Eights (Octet rule)
Outermost shell participates in bonding
Valence Shell
Forms when one atom in a pair gives up an electron and the others acquires it on permanent loan.
Ionic Bonds
Atoms that have complete valence shells (complete valence shells contain 8 electrons refer to Octet rule) are stable and do not form bonds.
Chemically Inert Elements
Ion
charged particles p+/=e-
Atoms gains electron(s) atom has a net- charge.
Anions
Atoms loses electron(s) atom has net + charge.
Cations
Formation of Anions and Cations
Anions and cations form when e- transfer between atoms-Forms after a metal loses electron(s) and nonmetal gains the electron(s).
Formed when atoms share a pair of electrons forms between two nonmetals.
Covalent Bond
Sharing two pairs (double) or three (triple).
Multiple Covalent Bonds
The attraction an atom has for electrons.
Electronegativity
Electron shared unevenly.
Polar covalent bond
Weak attraction between hydrogen (with a slight positive charge) and something else (negative charge). Holds water molecules to each other.
Hydrogen bonds
Attraction of unlike substances. When water molecules bond to the sides of a glass container.
Adhesion
Attraction of like substances. When water molecules bond to other water molecules.
Cohesion
The attraction of water molecules on the surface of water.
High Surface Tension
Attraction of water to the side of a small tube. Result of adhesion.
Capillary Action (capillarity)
Water dissolves many substances. Dissolves any substance with a charge. Forms a solution.
Universal solvent
Ice like most other pure substances has a crystalline structure. The structure is more spread out than liquid water.
Expands when freezes
Water’s ability to absorb a lot of heat before it gets hot. This makes water a good coolant.
High Specific Heat
A solution with a pH below 7 is
Acidic
An acidic solution has more
Hydrogen ions than hydroxide ions.
The substance in which the solute dissolves.
Solvent
Solutions in which water is the solvent are universally important to living things.
Aqueous Solution
The OH- ion. The free H+ ion can react with another water molecule.
Hydroxide ion
If the number of hydronium ions in a solution is greater than the number of hydroxide.
Base
This solution contains more hydroxide ions than hydronium ions.
Acid
Is the substance dissolved in the solution
Solute
