Periodic Trends Flashcards
periods
are rows on periodic table
groups
are columns on periodic table
alkali metals location and properties?
Group 1. low ionization energies, react explosively with water (Exothermic, always forms H2 gas), form ionic compounds
alkaline earth metals location and properties?
Group 2. low ionization energies, don’t react as violently with water, get more reactive with water as you go down the group
halogens location and properties?
Group 17 (with F, Clm BR, etc).highly electronegative, high electron affinities, highly reactive with metals, good oxidizing agents (they want to be reduced aka Gain Electron -GER)
noble gases
Group 18. inert (unreactive) gases
Transition metals located where? Form _____ compounds?
D block elements. form colorful compounds due to the way their d-orbitals behave
oxygen group, makes a good _____ agent?
O2 is a good oxidizing agent, but O3 is even better oxidizing agent. Likes to react with metals to form metaloxides
Metals make up _____ of the periodictable? Except where?
most of the periodic table, except top right corner and H
nonmetals are found where on periodic table?
top right corner + H
Metalloids are located where on periodic table?
create a diagonal line from B down to At in bottom right corner
atomic radius
the distance from a nucleus of an atom to the outside of its outermost orbital
bond length
the distance between two bonded atom’s nuclei
Why do atoms get larger as you go down a group?
higher energy shells “n” shell = larger size
Why do atoms get smaller as you move across a period, from left to right?
greater effective nuclear charge = smaller size. In other words, the more electronegative an atom (the more an element wants an e-), the smaller the atom. There are more protons to attract e- as you move left to right BUT you’re still in the same shell, so the protons hold everything closer/tighter together (smaller).
Do ion sizes increase or decrease with more e-?
more e- (anions) = larger size
less e- (cations) = smaller size
What is an isoelectronic series?
group of different elements that have the same number of e-
Ex: O-2, F-, Ne, Na+, Mg+2
In an isoelectronic series, how do you determine size?
By the number of protons. More protons means there is more strength to such e- in tighter making it SMALLER
ex: F-is smaller than Na+
ionization energy definition
energy required to remove an electron from an atom
what is the ionization energy trend on the period table?
increases as you go UP and to the RIGHT on periodic table (He has highest IE). We DO include noble gases
Where would it be the hardest or require the most energy to remove an e- at in accordance to ionization energy?
- Top right (He) requires the most energy to remove an e-
* bottom left requires the least amount of energy to remove on e- (Fr)
What is the size trend on periodic table?
get larger as you move down and to the left
Ionization energy AND electron affinity exceptions
1) Be is greater than B, full 2s2 so relatively stable
2) N greater than O, full 2p3 so it takes more energy to strip these e- bc it’s relatively stable
* Electron affinity is both 0 for Be and N
Is an atoms first ionizationenergy smaller or larger than its second? or its second compared to third?
smaller. (OR every successive ionization energy is larger than the previous one)
What does first Ionization energy, second IE or 3rd IE mean?
1st IE = first e- striped away
2nd IE = second e- removed
3rd IE = third e- removed
–takes more energy for every new e- removed
when would you have the LARGEST ionization energy for an atom?
When the atom feels like a noble gas, it’ll have HUGE IE bc it’s met the octet rule and doesn’t want to lose any e-
Electronegativity definition
how “thirsty” an atom is to gain e-
trend of electronegativity
increases as you move to the right and up, excluding the noble gases (F is the most electronegative)
electron affinity definition
the energy given off/produced when an atom gains an electron (basically the opposite of ionization energy)
is electron affinity endothermic or exothermic?
exothermic
What is the trend of electron affinity?
increases as you go UP and to the RIGHT. This trend is the same as electronegativity because it excludes noble gases. (chlorine (Cl) has the highest electron affinity, not F)
Why does Cl have a higher electron affinity than F?
Don’t need to know why. It just does. But F has greater electronegativity.