Unit 4 - Periodic Trends

Question 1

Period

Answer 1

horizontal row;

atomic numbers increase from left to right

Question 2

Family

Answer 2

vertical columns;

have similar properties

Question 3

Main group elements

Answer 3

first two families and last six families

Question 4

Transition elements

Answer 4

elements in the middle of the table

Question 5

Metals

Answer 5

tend to lose electrons to reach closest noble gas configuration;
metal oxides form basic solutions;
metallic character increases from right to left, top to bottom

Question 6

Non-metals

Answer 6

tend to gain electrons in order to become more stable;
generally lack 1, 2, or 3 electrons to fill shells;
non-metal oxides form acidic solutions;
non-metallic character increases left to right, bottom to top

Question 7

Metalloids

Answer 7

can gain or lose electrons to achieve noble gas configuration;
form amphoteric oxides which can react with acids or bases

Question 8

Noble gases

Answer 8

originally considered inert, however some of them can react;
can reach oxidation numbers up to +8;
stability comes from electron configuration as subshells are completely filled

Question 9

Atomic radius

Answer 9

decreases from left to right;
as nuclear charge increases, the outer electrons feel a stronger attraction so radius decreases
increases down a group;
as electron shells increase, atomic radius increases

Question 10

Factors that influence atomic radius

Answer 10

distance;
number of screening core electrons;
nuclear charge

Question 11

Ionic radius

Answer 11

cations are smaller than neutral atoms;
anions are larger than neutral atoms;
isoelectronic ions (same number of electrons) = size decreases as nuclear charge increases

Question 12

Ionization energy

Answer 12

energy required to remove an electron from a gaseous atom (positive value);
increases from left to right and bottom to top;
decreases as atomic radius increases because the electrons are held less strongly

Question 13

1st vs. 2nd ionization energy

Answer 13

1st = first electron removed;
2nd = second electron removed;
for each successive electron, required energy increases

Question 14

Filled and half-filled subshell effects

Answer 14

once the s-orbitals are filled, the orbital gains stability;
once the p-orbitals have on electrons in each, the orbital gains stability;
when an atom has greater orbital stability, the ionization energy and electron affinity increases

Question 15

Electron affinity

Answer 15

energy change that occurs when an electron is added to a gaseous atom;
increases from left to right and bottom to top;
decreases as atomic radius increases

Question 16

Electronegativity

Answer 16

how much an electron pulls on electrons when it is bonded to another atom;
increases from left to right and bottom to top;
increases with decreasing atomic size

Question 17

Fluoride and tooth decay

Answer 17

tooth decay occurs because tooth enamel (primarily hydroxyapatite) is decomposed due to addition of acid;
fluoride ions substitute spaces;
charges match, size fits, easy to deliver