periodic table and valence electrons

macronutrients

something that you must consume in large amounts 1 gram or more

micronutrients

essential to be healthy, milligrams or micrograms

water is not generally considered a nutrient because

it does not undergo chemical change in the body

columns on the periodic table

group numbers

rows on the periodic table

a period

properties of metals

1. shiny

2. mechanically strong, malleable( shapable) ductile ( can be spun into wire)

3. conductors of heat/ electricity

properties of non metals

1. not shiny

2. mechanically weak ( brittle)

3. not good conductors( insulators)

physical properties

can be observed or measured without changing its identity

chemical properties

behavior ( reactivity) in the presence of other elements

how are electrons arranged?

electrons are not evenly spread but exist in layers called shells

electron configuration

the arrangement of electrons in shells

chemical reactions happen when …..

two elements valence shells collide

compounds

a type of pure substance, that contains two or more elements, the elements have been chemically combined in a fixed ratio

valence electrons are responsible for…..

the formation of compounds

group number indicates….

how many valence electrons an element will have

each compound always has the same proportion of the same..

elements

a compound has an identity that is distinct from…

the elements that make it

types of bonds that describe compounds

ionic compounds: covalent compounds

octet rule

1) atoms with full valence shells are very stable

2) these atoms do not loose or gain electrons

3) all elements on the periodic table want to fill their valence shell ( like noble gases)

duet rule

hydrogen does not need 8 valence electrons, it only needs to gain or loose 1

ion

an atom that has an imbalance between its protons and electrons

cation

loses e - to become positively charged

anion

gains e- to become negatively charged