Is a substance that cannot be broken down to other substances by chemical reactions. 92 currently recognized.
A substance consisting of two or more differet elements combined in a fixed ratio.
Those elements required by an organism in only imnute quantities.
What is an example of trace element That is needed by all species?
The smallest unit of matter that still retains the properties of an element.
What are 3 types of subatomic particles?
Neutrons, Protons, Electrons
Which subatomic particle(s) is electrically charged?
Protons and electrons. Each proton has one unit of positive charge, and each electron has one unit of negative charge.
Protons and neutons packed together tightly in a dense core.
What is the unit of measurement for atoms and subatomic particles?
Dalton. (John Dalton, British scientist who helped develop atomic theory around 1800.) The dalton is hte same as the atomic mass unit, or amu)
What is the mass of a neutron or protron?
Close to 1 dalton
Why are Electrons ignored when computing the mass of an atom?
The mass of an Electron is only about 1/2000 that of a neutron or proton.
Number of protons, which is unique to an element. (written as a subscript to the left of the symbol for the element.)
The sum of the number of protons and neutrons in an atom's nucleus.
The total mass of an atom, which is the mass in grams of 1 mole of the atom.
One of several atomic forms of an element, ach with the same number of protons but a different number of neutrons, thus differeing in atomic mass.
An isotope (an atomic form of a chemical element) that is unstable; the nucleus decays spontaneously, giving off detectable particles and energy.
Is defined as the capacity to cause change -for instance, by doing work.
is the energy that matter possesses because of its location or structure.
An energy level of electrons at a characteristic average distance from the nucleus of an atom.
The chemical behavior of an atom is determined by what?
The distribution of electrons in the atom's electron shells - mostly on the number of electrons in its outermost shell.
An electron in the outermost electron shell.
The outermost energy shell of an atom, containing the valence electrons in volved in the chemical reactions of that atom.
The three-dimensional space where an electron is found 90% of the time.
How many electrons can occupy a single orbital?
No more than two at a time.
The sharing of a pair of valence electrons by two atoms.
Two or more atoms held together by covalent bonds.
A single covalent bond; the sharing of a pair of valence electrons by two atoms.
A type of molecular notation in which the constiuent atoms are joine by lines representing covalent bonds.
A type of molecular notation representing the quantity of constituent atoms, but not the nature of the bonds that join them.
A double covalent bond; the sharing of two pairs of valence electrons by two atoms.
What is the atoms bonding capacity called?
Valence...and usually equals the number of unpaired electrons required to complete the atom's outer most (valence) shell.
The attraction of a particular kind of atom for the electrons of a covalent bond.
Nonpolar Covalent Bond
A type of covalent bond in which electrons are shared equally between two atoms of similar electronegativity.
Polar Covalent Bond
A covalent bond between atoms that differ in electronegativity. The shared eletrons are pulled closer to the more electronegative atom, making it slightly negative and the other atom slightly positive.
An atom or group of atoms that has gained or lost one or more electrons, thus acquiring a charge.
A positively charged ion
A negatively charged ion
A chemical bond resulting from the attraction between oppositely charged ion.
A compound resulting from the formation of an ionic bond; also called salt.
A type of weak chemical bond that is formed when the slightly positive hydrogen atom of a polar covalent bond in one molecule is attracted to the slightly negative atom of a polar covalent bond in another molecule.
The conversion of light energy to chemical energy that is stored in sugars or other organic compounds; occurs in plants, algae and certain prokaryotes.
In a chemical reaction, the state in which the rate of the forward reaction equals the rate of the reverse reaction, so that the relative concentrations of the reactants and products do not change with time.
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