Chapter 5 chemistry

Valence electrons

Electrons in the outermost shell of an atom

Periods

back and forth rows on periodic table 7 rows

Groups

up and down sections of periodic table 18 sections

Main group elements

The s and p block combined

Ionization energy

amount of energy needed to remove an electron for an atom/ ion

Electronegativity

ability of atom to attract an electron from another atom

Electron shielding

blocking the positive charge with the shells between the nucleus and the valence electrons

Effective Nuclear charge

Amount of positive charge that acts on electron

Atomic radius

½ the distance between nuclei of identical atom bonded together

Periodic law

physical and chemical properties of elements are periodic functions of atomic number

Periodic table

arrangement of elements in order of their atomic number so the elements with similar properties will fall into the same column

Ionic radius

½ distance between center of 2 connected ions

Periodic trend

Predictable change in particular direction

How do you find valence electrons?

Subtract 10 from the group number

How do you find a element based off its period and groups?

Use them as coordinates

How do you find group and period based off electron configuration?

Go to where the last one would end and then count back to the number listed

How do you predict what elements will have similar properties?

In the same group and same number of valence electrons

Alkali metals

group 1

highly reactive

reacts strongly with water

easily forms compounds

stored in kerosene or mineral oil

soft, can cut with a knife

Alkaline earth metals

group 2

lees reactive than alkali

harder, denser, and stronger than alkali

pairs of electrons

lose 2 electrons to become stable

Transitional metals

groups 3-12

good conductors of electricity

less reactive than groups 1 and 2

high luster/ shiny

Metalloids

only 6

semiconductors of electricity

between metals and nonmetals

most are brittle solids

some properties of metals and nonmetals

Halogens

group 17

reacts with metal to form salt

7 electrons in outer energy level

Noble gases

group 18

8 electrons in outer energy level causes it to be stable

unreactive

does not readily gain or lose electrons

Lanthanides

Top row of f block

rare earth metals

atomic #57-71

reactive like group 2

shiny

used in tv, lasers, and strong magnets

Actinides

Bottom row of f block

atomic #90-103

all radioactive

1st four are natural, rest made in lab

uranium used for nuclear power

some are so unstable they only exist for a fraction of a second

Where are metals found?

groups 1-12

Where are metalloids found?

along the zigzag

Where are nonmetals found?

group 17 and 18

What is an ion?

atom with a charge

What is a cation?

positively charged ion, lost an electron

What is anion?

negatively charged ion, gained an electron

Where are the main group elements?

In the s and p blocks

What are the periodic trends for Atomic Radius?

decrease from left to right (bc of increasing nuclear charge) and increase going down a group (bc of an increase in number of electron shells)

What are the periodic trends for Ionic Radius?

decrease from left to right (bc of increasing nuclear charge) and increase going down a group (bc of an increase in number of electron shells)

What are the periodic trends for electronegativity?

increases from left to the right in the period because the effective nuclear charge increases and the atomic size decreases and decrease going down a group

What are the periodic trends for ionization energy?

increases from left to the right in the period because the effective nuclear charge increases and the atomic size decreases and decrease going down a group

Which scientist is given credit for the periodic table?

Dmitri Mendeleev

How was the first periodic table arranged?

by atomic mass

How is the current periodic table arranged?

It is arranged by atomic number