Chemistry Ch. 6
Atomic sizes increases from top to bottom within a group and decreases from left to right across a period of the periodic table.
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Currently elements are arranged on the periodic table according to increasing atomic number.
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Early scientists first sorted elements into groups according to their properties.
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Elements can be sorted into groups with similar properties based on their electron configuration, they have the same number of electrons in the outer orbitals.
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In Mendeleev's periodic table, elements we're arrange by increasing atomic mass.
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Ions with a positive or negative charge forms when electrons are transferred from one atom to another.
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Henry Moseley
A British physicist, determined an atomic number for each known element, performed X-rays
Dmitri Mendeleev
A Russian chemist and teacher, published a table of the elements, he arranged the elements in his periodic table in order of increasing atomic mass,
Halogen
A nonmetal in group 7A of the periodic table.
Ion
An atom or group of atoms that has a positive or negative charge.
Representative element
An element in an "A" group in the periodic table; as a group these elements display a wide range of physical and chemical properties. In their atoms, the s and p sublevels in the highest occupied energy level are partially filled.
Noble gas
An element in group 8A of the periodic table; the s and p sub levels of the highest occupied energy level are filled.
Inner transition metal
An element in the lanthanide or actinide series; the highest occupied s sub level and nearby f subtle bel of its atoms generally contain electrons; also called inner transition element.
Nonmetal
An element that tends to be a poor conductor of heat and electric current; nonmetal tend to have properties opposite to those of metals.
Metalloid
An element that tends to have properties that are similar to those of metals and nonmetals.
Cation
Any atom or group of atoms with a positive charge.
Anion
Any atom or groups of atoms with a negative charge.
Alkali metals
Any metal in group 1A of the periodic table.
Alkaline earth metals
Any metal in group 2A of the periodic table.
Johann Dobereiner
German chemist who published a classification system, known elements were grouped into triads, a triad is a set of three elements with similar properties, He was the first to suggest the existence of a relationship b/t the atomic mass and the properties of the element.
Atomic radius
One half the distance between the nuclei of two atoms of the same element when the atoms are joined.
Metal
One of a class of elements that are good conductors of heat and electric current; metals tend to be ductile, malleable, and shiny.
Transition metal
One of the Group B elements in which the highest occupied a sub level and nearby d sub level generally contains electrons.
Atomic size
Tends to decrease from left to right across a period and increase from top to bottom within a group.
Ionization energy
Tends to increase from left to right across a period and decrease from top to bottom within a group.
Electronegativity
The ability of an atom to attract electrons when the atom is in a compound.
Ionization energy
The energy required to remove an electron from an atom in its gaseous state.
Atomic number
The number of protons in the nucleus of an atom of that element.
Mass number
The total number of protons and neutrons in an atom.
Atomic mass
The weighted average of the masses of the isotopes of an element.
Electronegativity
Values decrease from top to bottom within a group and increase from left to right within a period.
Periodic Law
When the elements are arranged in order of increasing atomic number, there is a periodic repetition of their physical and chemical properties.
Ionic size
tends to increase from top to bottom within a group and decreases from left to right across a period.
