Periodic Table/trends Flashcards
Henry Moseley
Was 1st to arrange elements in a table format by atomic NUMBER
Dimitri Mendeleev
Produced 1st periodic table
- arranged elements according to atomic MASSES
- his table had empty spaces for elements yet to be discovered
Periodic law
When elements are arranged by atomic number, similar properties will exist in every 8 or so elements
Rows are called
Periods
Columns are called
Families or groups
Alkali metals
- 1st column/group
- reactive with water and air
- generally a 1+ charge
- soft metals (can cut with a butter knife)
- forms basic solutions
Alkaline earth metals
- 2nd column/group
- not as reactive as Alkali metals
- generally 2+ charge
- also somewhat soft metals
- forms basic solutions
Halogens
- 2nd last column/group
- very reactive non-metals
- generally a -1 charge
- F (g) Cl (g) Br (l) I (s) At (s) diff. phases
- forms acidic solution
Noble gases
- generally non-reactive (inert) gases
(some exceptions) - full outer shell
Transition metals
- d block
- metals in this group have MANY different charges
- results in colored solution
- tend to form metal complexes w/ certain ligands (attachments)
Metallic properties
Shiny, luste, malleable, ductile, conductive ect.
|———–non-metal
| I
|. I
Metal——————
Atomic size (radii)
- going down a column INCREASES atomic size. (orbitals get larger)
- going across from Left to Right, atomic size DECREASES
- if # protons increases it leads to a greater nuclear charge; can attract electrons closer in
Ion size (compared to neutral atoms)
- anions (-) will be LARGER than their neutral atom
- more e. w/ same # protons; smaller pull per e. - cations (+) will be SMALLER than their neutral atom
- fewer e. w/ same # protons; greater pull per e.
Ionization energy (IE)
- energy required to remove an outermost e. from a atom
- 1st IE -> energy required to remove first outermost e.- 2nd IE -> energy required to remove second outermost e.
DECREASES going down
- because e. are farther away from nucleus
INCREASES left to right
- because of greater nuclear charge (larger pull)
Electronegativity
- the ability of a nucleus to attract electrons towards its self WITHIN A BOND
DECREASES going down
- outermost e. is further away - > Shielding effect
INCREASES going left to right
- more protons; greater nuclear pull
Shielding effect
Inner e. will “shield” away some of the nuclear pull towards outer e.
Remember:
SIZE OVERPOWERS, # protons in the nucleus
- look at size first
Look up/down before left/right
These are trends - many exceptions exist
Lanthanides/Actinides
Radioactive