Periodic Table

Question 1

Jons Berzelius 1811

Answer 1

Also used the first letter of the element as the chemical symbol, discovered several elements, confirmed law of definite proportions, suggested other chemical symbols as more elements were discovered

Question 2

John Dalton 1808

Answer 2

First framework for symbols of the known elements (numbered 1-36, oxygen=#1 empty circle, all others had letters/inscriptions inside)

Question 3

Law of Definite Proportions

Answer 3

Compounds always have the same proportion of the elements that make them up

Question 4

Dmitri Mendeleev 1869 Periodic Table

Answer 4

Used increasing atomic mass for ordering, elements in the same column had similar properties, gaps were left for predicting new elements that would fit in with the others, first two rows had 7 elements, 3rd and 4th rows had 17 elements, “the properties of the elements were in periodic dependence with atomic mass”

Question 5

Noble gasses (1890-1900)

Answer 5

Sir William Ramsay isolated helium (had been known through the sun) from terrestrial sources, he was involved in the discovery of Ne, Ar, Kr, and Xe, and added another column to Mendeleev’s table

Question 6

Periodic Law (1914)

Answer 6

Henry Mosely showed proton variance from one element to another through X-Rays, concluded elements were missing when X-Ray results varied (new arrangement solved most of the gaps). Periodic = is the physical and chemical properties of elements are periodic functions of their atomic number.

Question 7

Glen Seaborg 1940

Answer 7

Discovered transuranium elements up to 102, positioned the series of lanthanide and actinide, named 106 after himself

Question 8

Groups 3-12

Answer 8

Transition metals, d block, typical properties

Question 9

Groups 13-18

Answer 9

Main group elements, p block

Question 10

Group 17

Answer 10

Halogens: halas=salt, gen=to generate

Question 11

Group 18

Answer 11

Noble gasses

Question 12

Lanthanide and Actinide series

Answer 12

F block, lanthanides are similar to alkali earth metals, actinides are radioactive

Question 13

Most active metal

Answer 13

Francium

Question 14

Most active non-metal

Answer 14

Fluorine

Question 15

Atomic radius

Answer 15

Decreases as atomic # increases across a period (electrons are pulled closer as more positive charge is present), and increases going down a group (electrons occupy a higher main energy level)

Question 16

Ionization Energy

Answer 16

Energy required to remove one electron (and subsequent electrons) from a neutral element of an atom

Question 17

Main Group Elements (IE)

Answer 17

Increases across a period, decreases down a group

Question 18

Metals, Metalloids, Nonmetals (IE)

Answer 18

Metals = low, nonmetals = high, noble gasses = unusually high)

Question 19

Successive Removal of Electrons

Answer 19

Each is harder because there are fewer electrons to shield the attractive forces of the nucleus

Question 20

Ionization Equation

Answer 20

A + energy –> (A+) + (e-)

Question 21

Across a period…

Answer 21

Cations become smaller, then anions become smaller

Question 22

Down a group…

Answer 22

The ionic radii increase similarly to atomic radii

Question 23

Electronegativity

Answer 23

Measure of an atom’s ability to attract electrons in a chemical compound (usually increases going across a period and decreases/stays the same down a group, especially for transition metals)

Question 24

Most electronegative?

Answer 24

Fluorine

Question 25

Most electropositive?

Answer 25

Francium

Question 26

Electron Affinity

Answer 26

Energy change that occurs when an electron is acquired by a neutral atom

Question 27

When most atoms acquire an electron…

Answer 27

They release energy

Question 28

Electron Affinity Trends

Answer 28

In a period, values generally become more negative. Exception is noted between 14 and 15 (single electron vs. putting in second electron in orbit). Going down a group is typically more difficult to add electrons, but nuclear charge and atomic radii play a role.