ch 2 - periodic properties Flashcards
group 1 elements
alkali metals
- excluding hydrogen
group 2 elements
alkaline earth metals
group 3-12 elements
transition metals
groups 13-17 elements
metalloids
- has a combination of both metaallic nd non-metallic characteristics
group 17 elements
halogens
group 18 elements
noble gases
period 6 and 7 elements
inner transition metals
- separated from the transition metals because their properties differ
period 6 elements
lanthanides
period 7 elements
actinides
what are the 7 diatomic atoms
hydrogen, nitrogen, fluorine, oxygen, iodine, chlorine, bromine
- Have No Fear Of Ice Cold Beer
how does metallic character increase on the periodic table
going right to left across a period
- and going down a group
characteristics of metals
malleable, lustrous
- good conductors of electricity, heat
- form basic oxides
- lose electrons to form cations
- usually solid at liquid temperature, with the exception of Hg (liquid)
- generally, high melting and boiling points
characteristics of non-metals
brittle, dull
- poor conductors of electricity/heat
- form acid oxides
- gain electrons to form anions
- gas or solid at room temperature, with the exception of Br (liquid)
- generally, low melting and boiling points
atomic radius: definition, trend, and reasoning
definition
- half the distance between the nuclei of two identical atoms bonded together
trend
- the atomic radius decreases from left to right across a period and increases going down a group
reasoning
- across a period, the number of protons in an atom increases
- increasing protons results in greater nuclear attraction between the protons and electrons, which results in shells being pulled closer to the nucleus (which equals a smaller radius)
- going down a group, the number of electrons increases
- each additional energy level gets farther and farther away from the nucleus, which causes the atomic radius to increase
effective nuclear charge: definition, trend, reasoning
definition
- the effective nuclear charge (Zeff) is the nuclear charge experienced by an electron in an atom with multiple electrons
- this charge is assigned due to a shielding effect of electrons preventing other electrons in higher orbitals from experiencing a strong attraction to the nucleus
- this effect explains why valence electrons are more easily removed
- effective nuclear charge equation: Zeff = Z-S, where Z = # of protons, S = # of shielding electrons
trend
- effective nuclear charges increases across a period from left to right and decreases going down a group
reasoning
- across a period, the number of protons are increasing with no increase in a shielding effect, which results in electrons being pulled closer to the nucleus due to a stronger attraction
- going down a group, more shielding causes the effective nuclear charge to decrease
- as electrons get further away from the nucleus, the attractive force between protons and electrons naturally lessens
what is the equation for effective nuclear charge?
Zeff = Z - S
- Z = number of protons
- S = number of shielding electrons
shielding effect
electrons in higher orbitals do not have strong attraction to nucleus due to shielding effect of closer electrons
- explains why valence electrons are more easily removed
- the electrons between the electron of interest and nucleus cancels some of the positive nuclear charge → resulting in a weaker attraction
part of effective nuclear charge
when a neutral atom loses an electron and becomes a cation, what happens to effective nuclear charge & radius?
the effective nuclear charge increases, which causes the radius to decrease
- this is because protons will pull in electrons closer to the nucleus
when a neutral atom gains an electron and becomes an anion, what happens to effective nuclear charge & radius
atomic radius will increase, due to a decrease in effective nuclear charge
- causes a decrease in the pull from the protons in the nucleus
do metals usually form anions or cations?
they typically form cations
- resulting in their ionic radius to be less than their atomic radius
do non-metals usually form anions or cations?
they typically form anions
- resulting in their ionic radius to be greater than their atomic radius
isoelectronic series: definition only
these are atoms that have the same electron configuration, but differing number of protons
- in this case, the most positively charged atom will have the smallest radius because it has the most protons with the same number of electrons
- therefore will have the greatest attraction to the nucleus
do anions or cations have a larger radius
anions have a larger radius than cations
Q: which of the following ions has the smallest radius?
a) Na+
b) Br-
c) S2-
d) P3-
e) Al3+
Al3+
- can eliminate anions as a potential answer because anions have a larger radius than cations
- when comparing Na+ and Al3+, you should be able to determine that these cations are isoelectronic
- however, since Al3+ has more protons, the electrons will experience a greater pull resulting in a smaller radius