Periodic Trends Flashcards

Terms Definitions
group 17
row, horizontal across table
family, column vertical down table
semiconductors, a crystalline material with good conductors at high temperatures and insulators at low temperatures
realized spectral lines matched atomic number, not atomic mass
The most electronegative element ____ has an electronegativity value of 3.98, according to the Pauling scale, devised in 1932 by Linus Pauling.
Electronegativity decreases going from ____ to ____ in a period.
right, left
Size of AtomAtoms that have larger number of electrons will occupy more space, because electrons occupy the largest volume in the atom.The nucleus occupies very little spacemore e-, the bigger the atomexception: when adding e- to same shell, as proton increase, slight shrinkagePeriodic Trends: Size of Atomsatomic radius depends on how it is measured*In condensed solid phase for nonbonding atoms that are in direct contact; van der Waals radius or nonbonding radiusBonding or covalent radius:*Nonmetals: one-half of the distance between two of the atoms bonded together*Metals one half of the distance between two of the atoms next to each other in a crystal of the metalTrend in Atomic Radiusdown column: radius increase- n number increases down a group - most of size of atom due to shells where e- are; increase in n means increase in sizeEffective Nuclear Charge: see txtIon Configuration* see txtremove or add: highest prin. quantum # orbitalespecially for transition metalsIonic Size vs. Atomic SizeIonic radius = estimate of the size of an ion in a crystalline ionic compoundCations are smaller than their parent atomse- are removed from the outer level., decrease in repulsions allows nuclear charge to pull the remaining electrons closerAnions are larger than their parent atomse- are added to the outer level. the increase in repulsions causes the e- to occupy more spaceIonic radiusin iso-electronic series, anions are larger than neutral atoms which are larger than cationsIonization Energy:energy required to remove a mole of e- from a mole of atom or ion in the gas phase. Positive (endotherm H) First ion. Energy IE1: energy req. to remove the outermost first e- of a neutral atomn dec down groupinc. left to right;;..
a negatively charged ion, formed when an atom gains one or more electrons
ionization energy
increases across a period because decreases down a group
elements that are poor conductors of electricity but a good insulators
Acidity ____ going down a group, because the size of elements increases going down a group.
What is an Octet?
A group of eight electrons.
atomic radius
across: electrons added to the same energy level experience increasing attraction to the nucleus due to successive addition of protons.
down: each period on the table adds a new energy level to the electron cloud.
measure of how much an atom attracts other electrons towards it
a gas composed of ions, electrons, and neutral particles
What is an Ion?
Contains a negative or positive charge.
a solid or liquid solution of two or more metals
Which is the least electronegative element?
Cesium (does not attract electrons)
atomic radius
(trend on the periodic table)
decreases across a period
increases down a group
What is Atomic Radii?
The distance from the center of an atom's nucleus to its outermost electron (how big the atom is)
melting/ boiling point
high MP means high IMF, low MP means low IMF
(trend on the periodic table)
cations are smaller than the atom from which they are formed
Why does ionization energy DECREASE as you move DOWN the periodic table?
Atoms become larger as you move down the periodic table. The larger the atom, the less energy is needed to remove an electron, making the energy needed to lose an electron decrease as you move down the table.
group 1
alkali metals
responsible for characteristic shape of periodic table and the first 63 elements by atomic mass although there were gaps in the table
increasingly negative going right, increasingly positive going down
Electron affinity
responsible for first periodic table with the first 16 elements
Electronegativity ____ going across a period (from left to right).
a positively charged ion, formed when an atom loses one or more electrons
transition metals
elements in Groups 3 - 12
elements that are good conductors of electricity
allotropes have diff physical properties
different bonding between atoms
periodic law
used by Meneleev to organize the physical and chemical properties of elements and their atomic numbers
electron shielding
electrons in lower energy levels block the effective positive charge of the nucleus from valence electrons
ion energy
the amount of energy needed to remove an electron
atomic radius
the radius of an atom (since the electron cloud accounts for the volume of the atom, this is primarily the radius of the electron cloud)
What is Electron Affinity?
The energy needed to gain an electron.
van der Waals radius
half the distance between the nuclei in adjacent nonbonded molecules
Which is the most electronegative element?
Fluorine (strong ability to attract electrons)
Why does ionic radius DECREASE as you move ACROSS the periodic table?
Increased number of protons-->the greater the number of protons, the stronger the attractive force from the nucleus. Valence electrons are pulled by this towards the nucleus, making the atom smaller.
(trend on the periodic table)
anions are larger than the atom from which they are formed
What do atoms with higher electron affinity have?
The ability (need) to gain electrons to fill the outer energy level.
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