Chemistry 1A Terms From Chapter 2 Of General, Organic, & Biological Chemistry

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alkali metals

Back 1

Elements of Group 1A (1) except hydrogen; these are soft, shiny metals with one outer shell electron.

Front 2

alkaline earth metals

Back 2

Group 2A (2) elements, which have 2 electrons in their outer shell.

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atom

Back 3

The smallest particle of an element that retains the characteristics of the element.

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atomic mass

Back 4

The weighted average mass of all the naturally occurring isotopes of an element.

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atomic mass unit (amu)

Back 5

A small mass unit used to describe the mass of very small particles such as atoms and subatomic particles; 1 is equal to one-twelfth the mass of a ¹²C atom.

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atomic number

Back 6

A number that is equal to the number of protons in an atom.

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atomic spectrum

Back 7

A series of lines specific for each element produced by photons emitted by electrons dropping to lower energy levels.

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atomic symbol

Back 8

An abbreviation used to indicated the mass number and atomic number of an isotope.

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chemical symbol

Back 9

An abbreviation that represents the name of an element.

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compound

Back 10

A pure substance consisting of two or more elements, with a definite composition, that can be broken down into simpler substances by chemical methods.

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d block elements

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The block ten-elements wide in Groups 3B (3) to 2B (12) in which electrons fill the five d orbitals in d sublevels.

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electron

Back 12

A negatively charged subatomic particle having a very small mass that is usually ignored in mass calculations; its symbol is e-.

Front 13

electron configuration

Back 13

A list of the number of electrons in each sublevel within an atom, arranged by increasing energy.

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electron-dot symbol

Back 14

The representation of an atom that shows valence electrons as dots around the symbol of the element.

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element

Back 15

A pure substance that cannot be separated into any simpler substances by chemical methods.

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f block elements

Back 16

The block 14-elements wide in the rows at the bottom of the periodic table in which electrons fill the seven f orbitals in 4f and 5f sublevels.

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group

Back 17

A vertical column in the periodic table that contains elements having similar physical and chemical properties.

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halogen

Back 18

Group 7A (17) elements of fluorine, chlorine, bromine, iodine, and astatine.

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ionization energy

Back 19

The energy needed to remove the least tightly bound electron from the outermost energy level of an atom.

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isotope

Back 20

An atom that differs only in mass number from another atom of the same elemet. They have the same atomic number (number of protons) but different numbers of neutrons.

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mass number

Back 21

The total number of neutrons and protons in the nucleus of an atom.

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matter

Back 22

anything that has mass and occupies space.

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metal

Back 23

An element that is shiny, malleable, ductile, and a good conductor of heat and electricity. These are located to the left of the zigzag line in the periodic table.

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metalloid

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Elements with properties of both metals and nonmetals located along the heavy zigzag line on the periodic table.

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mixture

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The physical combination of two or more substances that does not change the identies of the mixed substances.

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Neutron

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A neutral subatomic particle having a mass of 1 amu and found in the nucleus of an atom; its symbol is n or n^0.

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noble gas

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An element in Group 8A (18) of the periodic table, generally unreactive and seldom found in combination with other elements.

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nonmetal

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An element with little or no luster that is a poor conductor of heat and electricity. These are located to the right of the zigzag line in the periodic table.

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nucleus

Back 29

The compact, very dense center of an atom, containing the protons and neutrons of the atom.

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orbital

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The region around the nucleus where electrons of a certain energy are more likely to be found. The s's are spherical; the p's have two lobes.

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orbital diagram

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A diagram that shows the distribution of electrons in the orbitals of the energy levels.

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p block elements

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The elements in Groups A 13) to 8A (18) in which electrons fill the p orbitals in the p sublevels.

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period

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A horizontal row of elements in the periodic table.

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periodic table

Back 34

An arrangement of elements by increasing atomic number such that elements having similar chemical behavior are grouped in vertical columns.

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proton

Back 35

A positively charged subatomic particle having a mass of 1 amu and found in the nucleus of an atom; its symbol is p or p+.

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pure substance`

Back 36

A type of matter with a fixed composition: elements and compounds.

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s block elements

Back 37

The elements in Groups 1a (1) and 2A (2) in which electrons fill the s orbitals.

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Subatomic particle

Back 38

A particle within an atom; protons, neutrons, and electrons are examples of these type of particles.

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sublevel

Back 39

A group of orbitals of equal energy within principal energy levels. The number of sublevels in each energy level is the same as the principal quantum number (n).

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valence electrons

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Electrons in the outermost energy level of an atom.