Chemistry Unit 2 - Periodic trends

Metals 

• shiny 

• bend 

• lose electrons easily 

• conduct heat and electricity well 

Non- metals

• don’t have luster

• can’t be bend easily

• usually gain or share electrons instead of losing them

• They hold onto electrons tightly 

• don’t conduct heat or electricity well. 

Metalloids

Metalloids are elements that have properties of both metals and nonmetals.

what group are halogens in and what are they

G 17, Highly reactive nonmetal elements that usually want to gain one electron to fill their outer shell.

• greedy for electrons (high electronegativity)

• forms salts when they react with metals.

Alkali metals

• G1

• soft

• extremely reactive (especially with water)

• easily lose 1 electron to form positive ions

Alkaline earth metals 

• G2 

• slightly less reactive metals 

• lose 2 electrons to form positive ions 

• harder than alkali metals 

• reacts with water (not as much as the Alkali metals) 

Transitional metals

• In the middle of the periodic table

• - can form diff positive ions

• good conductors of heat and electricity

• strong

• can have more than 1 oxidation state: can lose diff numbers of electrons and can have diff charges

• can be colorful: jumps around so they absorb and reflect, we see light.

oxidation states 

How many electrons they can lose 

Lanthanides

• top row of the bottom block of the periodic table

• shiny metals and usually rare earth elements

• usually used in tech

Actinides

• Bottom row of the bottom block of the periodic table

• mostly radioactive metals

• used in nuclear energy and weapons

Reactive elements 

Reactive means an element easily reacts with other elements to form compounds. “Likes to make chemical friends quickly” 

Atomic radius

How big the atomic is; Distance form an atom’s nucleus to its outermost electron shell, showing how large the atom is.

first ionization energy

How much energy it takes to pull an electron off an atom

Electronegativity 

How strongly an atom pulls electrons towards itself when its sharing them in a bond; how much an atom wants to keep electrons when it’s near another atom. 

Periodic trend for Atomic radius

Increases from the top to bottom, increases from right to left.

Periodic table for first ionization energy

Increases bottom to top, increases from the left to the right.

Periodic trends for electronegativity 

Increases from the bottom to the top, increases from the left to the right. 

• same as first ionization energy. 

Periodic trends for metallic 

Increases from the top to the bottom, from the right to the left. 

• same as the atomic radius. 

Factors that affect the attraction between an electron and the nucleus:

• Amount of protons (amount o charge of the particles.)

• Amount of shells (Distance between particles)

• Amount of electron shielding (Amount of core electrons/amount of nuclear charge)

Electronegativity trend 

increases from bottom to the top; left to right 

What is electronegativity 

How strongly an atom pulls electrons towards itself when it’s sharing them in a bond.

Reason for attraction

• # of protons: More protons = more stronger pull, less protons = less stronger pull.

• # of shells: More shells = farther away from the nucleus; less attraction, Less shells = closer to the nucleus; more attraction.

• Electron shield: The core electrons can prevent the attraction the V.E feel because electrons all have a neg charge. this neg charge repels the electrons which makes the attraction weaker.