Chem Final

rare earth elements

(inner transition elements) composed of lanthanide (top; +3 oxidation states, extremely similar chemically) and actinide (bottom; radioactive, dense, tarnishable)

ion

An atom or group of atoms that has a positive or negative charge.

Mendeleev's periodic table

Elements arranged in order of INCREASING MASS. Elements with similar properties fell into groups on the table. 63 Elements known at this time.

ionization energy

The amount of energy required to remove an electron from an atom; increases going across periods and decreases going down groups; (big radius, low ionization energy) elements on the left side of the periodic table have low ionization energies because of their willingness to lose electrons and become cations

chemical bond

a mutual attraction between the nuclei and valence electrons of different atoms that binds the atoms together (positive and negative attraction)

octet rule

atoms react by gaining or losing electrons so as to acquire the stable electron structure of a noble gas, usually eight valence electrons (cations loose and have a positive charge while anions gain and have a negative charge)

you can find the degree to which bonding between atoms of two elements is ionic or covalent by...

calculating the difference in the element's electronegativity

ionic bond

chemical bonding that results from the electrical attraction between cations and anions; in purely ionic bonds, atoms give up electrons to other atoms

Lewis structure

compounds that use electron dot diagrams to show bonding; shows how multiple atoms bond using dots and dashes representing unshared and shared electrons

non-metals bonding with non-metals or metalliods form....

covalent bonds

bond energy

energy required to break a covalent bond

alkali metals

first column (under hydrogen), one VE, shiny and silver, soft, low melting point and density (floats in water), most reactive metals (violently reacts with water), never found alone in nature

hydrogen group

gas, class of its own, one VE, in the same group as alkali metals because its properties are very similar

halogens

group 17, 7 VE, most reactive non-metals, will do anything to fill their energy level and reach a stable octet, very aggressive

noble gases

group 18, 8 VE, most nonreactive, inactive because they have a stable octet (inert)

alkaline earth metals

group 2, two VE less reactive, harder, denser higher melting point, never found alone in nature

transition metals

groups 3-12, transition from metals to metalloids, good heat and electricity conductors, rage from one to four VE, least reactive, densest, hardest, highest melting point, some found alone in nature, many bond with oxygen to from oxides

independent particles...

have high potential energy but nature prefers low potential energy so bonding occurs to lower the particle's potential energy

electronegativity difference of 4.0 to 1.7 is ...

ionic

non metals bonding with metals from...

ionic bonds

structural isomers

molecular compounds with the same composition but different structures

covalent bonding forms...

molecules

shorter bond length need ...

more energy to break it (inverse relationship)

group 13-16

named after the top element, valence electrons are ten less than the group it is located in (group 14 has 4 VE); group 16 combines with almost all elements

electronegativity difference of 0.3 to 0 is ...

non-polar covalent (electrons shared equally)

trends

patterns in the periodic table; group-top to bottom (reactivity increases in alkali metals) period-left to right (increase in VE)

Moseley's periodic table

periodic table in which the elements are arranged by increasing ATOMIC NUMBER and by changes in chemical properties. 93 elements known at this time.

electronegativity difference of 1.6 to 0.4 is ....

polar-covalent (electrons shared unequally)

bonding is rarely.....

purely ionic or covalent

covalent bond

results from the sharing of electrons between two atoms; in purely covalent bonds, the shared electrons are "owned equally" by the boned atoms

orbital blocks

s block - hydrogen, alkali and alkaline earth metals p block - group 13-16, halogens, noble gases d block - transition elements f block - lathanides, actinides *the number of columns in a block corresponds to the maximum number of electrons that can occupy the particular sublevel of that block. the row number in the periodic table is equal to the N value of the highest principal level.*

3 elements Mendeleev predicted

scandium, gallium, germanium

structural formula

shows only the bonding electrons using dashes

atomic radius

size of an atom; decreases going across periods because more protons and electrons (they attract each other) are added to an atom causing the atomic cloud to pull closed to the nucleus making the size of and atom smaller. increases going down groups because the number of electrons increases so the number of energy levels increases making the size of an atom bigger.

metallic bonding

the chemical bonding that results from the attraction between metal atoms and the surrounding sea of electrons

bond length

the distance between adjacent nucleii in a molecule (locked in distance)

electronegativity

the measure of an atoms attraction to electrons of another element: increases going across periods and decreases going down groups; scale of 0-4 where 0 doesn't want electrons and 4 does. NOBLE GASES ARE NOT COUNTED!!!! left side of the table has the lowest electronegativity the energy required to gain electrons is significantly higher compared with the energy required to lose electrons.

valence electrons

the outermost electrons on the highest energy level (groups 18)

ionic radius

the size of an ion compared to the original atom. metal atoms lose electrons and form positively charged ions that are smaller than the original atom (cations), nonmetal atoms form negatively charged ions that are larger than the original atom (anions).

atoms bond to....

to become more stable (stable octet); they want to look like noble gases

electron dot diagram

uses the elements symbol to represent the nucleus and inner electrons and the dots represent the valence electrons. (at most eight dots for each elements only only two dots in each quadrant)