Periodicity

Question 1

Moseley PT

Answer 1

Current. Increasing atomic number going across in periods and similar properties going down in groups

Question 2

Mendeleev PT

Answer 2

Past. By atomic mass in groups and properties in periods

Question 3

Mendeleev gaps in PT

Answer 3

There were gaps in places where no known element could fit. Scientists had to predict it.

Question 4

The periodic Law

Answer 4

groups go up and down with simialr properties and periods go across with atomic number

Question 5

atomic radii def

Answer 5

half the distance between 2 nuclei of the same element

Question 6

ionic radii def

Answer 6

size of the changed atom after becoming an ion

Question 7

electronegativity def

Answer 7

the tendency to attract e- from another element’s atom when chemically combining

Question 8

ionization energy def

Answer 8

measures the energy required to move an e- from outermost level

Question 9

electronaffinity def

Answer 9

energy lost when an atom gains e-

Question 10

atomic radii trend

Answer 10

increases going down & decreases across

Question 11

ionic radii trend

Answer 11

neutral atoms increase going across & decrease going down

Question 12

electronegativity trend

Answer 12

increase across and decrease down groups

Question 13

ionization energy trend

Answer 13

increases across and decreases going down

Question 14

reactivity trend

Answer 14

increases across and decreases down

Question 15

valance e- trend

Answer 15

increase across table and remains the same down

Question 16

nuclear effect

Answer 16

The attractive positive charge of nuclear protons acting on valence electrons.

Question 17

shielding electrons

Answer 17

the blocking of valence shell electron attraction by the nucleus, due to the presence of inner-shell electrons.

Question 18

valance e- distance from nucleus

Answer 18

can increase and decrease radii because the farther the vale- the more shielding electrons but make the radii larger from added protons. When vale- are closer to nucleus the vale- are easier to lose making a smaller radii

Question 19

number of occupied energy levels

Answer 19

additional occupied energy levels, increase going down and get more e- added to same energy level going across.

Question 20

charge density

Answer 20

The periodic trend is that charge density decreases as one moves down the periodic table because the charge remains constant, but the size increases. As the charge increases and the size decreases, the charge density increases across

Question 21

Atoms are

Answer 21

neutral

Question 22

cations

Answer 22

lose e-, positive, metals, smaller than neutral atom

Question 23

Anions

Answer 23

gain e- , negative, nonmetal, bigger then neutral atom

Question 24

Ions

Answer 24

charged are stable like noble gasses w/ 8 vale-

Question 25

noble gasses

Answer 25

are stable=inert= dont react during normal conditions, w/ vale-

Question 26

octet rule

Answer 26

every atom wants to be a stable like a noble gas with 8 vale-