Chapter 5 Flashcards
Dalton
- published the first list of elements
- Put them in atomic weight from lowest —> highest
Dobereiner
- DIDN’T look at elements by weight
- Created triads(groups of 3)
*Problem: not all the elements were grouped/grouped improperly b/c it doesn’t work in every element
Bunsen
- Invented the bunsen burner and spectroscope
*This comes up with a new way to find and identify elements
Mendeleev
- Published the 1st periodic table(1869)
- Was missing a whole group(noble gasses)
Ramsey
Discovered noble gasses and made them a group(1900s)
Mosley
- Created the atomic number
- an’t have half a proton so nothing in between
*Could only have 92 elements - His 1st periodic table(1913)
Berzelius
- Glass-blowing guy
*Coming up with accurate atomic weights - Wanted to organize the elements more accurately than Dalton
Newlands
- Created the Law of Octaves
*Every eighth element had similar properties - Concept is still used today(Periodic Law)
Periodic Law
a law saying the elements, when listed in order of their atomic numbers, will fall into recurring groups with other similar properties
Periodic Trend
- are consistent changes in properties as you move across a period
*period: horizontal groups on the table
Group Trend
- are consistent changes in properties as you move down a group/family
*group/family: vertical columns on table
Atomic radius
- distance from the center of the nucleus → outer edge of electron cloud
*More electrons/energy levels = bigger atom which means larger radius
Periodic/group trend for atomic radius
Radius decreases across periods
Radius increases down families/groups
Valence energy level
- Outermost electrons will ALWAYS be in the s and p sublevels
- MOST valence electrons you will ever see is 8(s(2) & p(6))
Valence electrons
electrons in the outermost energy level
Octet rule
- 8 electrons in the outermost energy level (filled s & p sublevels) is the most stable electron configuration
- Subgoals:
*Full last-filled sublevel
*Half-full last-filled sublevel
Ions
atoms or molecules that are not neutral
Ionization
- process that results in forming an ion
*Happens by adding or removing electrons
*NO ion does ionization alone (paired process)
Ionization energy
measures how much energy it takes to remove an electron from an atom
*Higher IE → harder to steal from
1st, 2nd, 3rd, etc ionization energy
Energy needed to take the 1st, 2nd, 3rd, and etcetera electron
Electronegativity
is a measure of the ability of an atom in a chemical compound to attract electrons from another atom in the compound.
Period/group trends for electronegativity
Increases across periods
Increases down groups/families
Key discoveries/work of scientists in order
- Dalton published the 1st list of elements by order of atomic weight from lowest to highest
- Berzelius, who was the glass-blowing guy. * Dobereiner observed elements by their chemical properties in triads
- Bunsen invented the bunsen burner and spectroscope
*Newlands created the Law of Octaves - Mendeleev published the first periodic table
- Ramsey added the group known as the noble gasses
- Moseley introduces the atomic number
First periodic table (how it was arranged, what was missing)
- The first periodic table was arranged by atomic weight
- The group known as the noble gasses was missing from the table.