M

magic number main-group element
malleable manometer
mass mass defect
mass number mass spectrometer
mass spectrum matter
mean free path melting
melting point meniscus
messenger RNA meta
metal metallic radius
metalloid metallurgy
meter miscible
mixture mohr pipet
molality molar mass
molar solubility molarity
mole mole fraction
molecular formula molecular orbital
molecular orbital diagram molecular orbital theory
molecular weight molecule
monomer mRNA
multidentate  




magic number

One of the numbers 2, 8, 20, 50, 82, and 126; nuclei having this number of neutrons or protons (or both) exhibit great stability.


main-group element

One of the elements in the area of the periodic table over which the s and p atomic orbitals are being filled; also called representative element.


malleable

Able to be pounded into shape


manometer

A device for measuring the pressure of a gas in relation to the pressure of the atmosphere.


mass

A measure of the quantity of matter; the force required to impart unit acceleration to an object.


mass defect

The difference in mass between an atom and the atoms from which it could be formed. This difference is released as energy in a nuclear reaction.


mass number

The sum of the numbers of protons and neutrons in an atom; these two kinds of particles contain almost all of the mass of an atom.


mass spectrometer

An instrument that measures the mass of ions by accelerating them through electric and magnetic fields.


mass spectrum

The record of fragments formed in a mass spectrometer presented as a plot of abundance against atomic mass.


matter

Anything that occupies space and has mass; contrasted with energy.


mean free path

The average distance that gas molecules travel between collisions.


melting

The process of a liquid forming from a solid.


melting point

The temperature at which a solid becomes a liquid. Also called freezing point.


meniscus

The meniscus is the curvature of a liquid in a vessel at the liquid air interface. It is caused by attractive forces between the solution and the walls of the vessel. In cases where the solution wets the sides of the vessel, you should measure the volume from the bottom of the meniscus. Position the vessel so that your eyes are level with the bottom of the meniscus as shown above. If your eye level is above or below the line of sight shown in the picture, your reading will be in error.


messenger RNA

The RNA that conveys information from the genetic code on DNA to a ribosome where transfer RNA attaches the correct amino acid to a growing protein; abbreviated mRNA.


meta

Describing the relationship between two groups attached to carbon atoms on a benzene-like ring which have one carbon atom between them.


metal

An element characterized typically by a glossy surface, thermal and electrical conductivity, malleability, and ductility.


metallic radius

The distance between atoms in a metal; found from the internuclear distance.


metalloid

An element having properties intermediate between a metal and a non-metal.


metallurgy

The study of metals and their extraction from ores.


meter

The SI unit for distance.


miscible

Able to dissolve in each other in any proportion.


mixture

A combination of two or more substances in which the substances retain their chemical identity.


mohr pipet

This is a Mohr pipet. It is used for transferring specified volumes of liquid from one container to another.


molality

A concentration unit expressed as moles of a substance per kilogram of solvent.


molar mass

The mass of a mole of substance; the same as molecular weight for molecular substances.


molar solubility

The extent to which a solute dissolves in a solvent expressed as the number of moles of a substance that will dissolve per 1 L of solution.


molarity

A concentration unit expressed as moles of a substance per liter of solution.


mole

That amount of a substance containing the same number of units as 12 g of carbon-12.


mole fraction

In a mixture, the number of moles of one substance divided by the total number of moles of all substances present.


molecular formula

The chemical formula of a substance written using the subscripts that reflect the number of each atom present in a molecule of the substance.


molecular orbital

An orbital formed by the overlap of atomic orbitals; designated as bonding, non-bonding, or anti-bonding.


molecular orbital diagram

A diagram depicting the relative energies and the occupancy of the molecular orbitals in an ion or molecule.


molecular orbital theory

The theory that describes covalent bonding in terms of orbitals that are formed by the combination of atomic orbitals on different atoms.


molecular weight

The mass of one mole of molecules of a substance; the molar mass of a molecular substance.


molecule

A set of atoms joined by covalent bonds and having no net charge.


monomer

One of the units that joins with other units to form a polymer.


mRNA

Abbreviation for messenger RNA; the RNA that conveys information from the genetic code on DNA to a ribosome where transfer RNA attaches the correct amino acid to a growing protein.


multidentate

Referring to a ligand attached to a central metal ion through two or more atoms.



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