8th grade Chemistry Mid Unit Recap

8th grade Chemistry Mid Unit Recap

by John PineHollowMS

Positive Charge

​

Found in the Nucleus

​

Has mass! (1 AMU)

​Proton

Neutral/No Charge

​

Found in the Nucleus

​

Has mass! (1 AMU) ​

​Neutron

​Negative Charge

​

Found outside the Nucleus

​

Has very very little mass​

​Electron

​How to find Protons, Neutrons, & Electrons

​# of  protons = atomic #

because # of protons determines an element's atomic identity

​

# of neutrons = mass #  - atomic #

because protons and neutrons together make the atomic mass

(round to the nearest whole number!!!)

​

# of electrons = # of protons, if charge = 0

because protons and electrons must cancel each other out

​5

​B

Boron

10.81​

Atomic #

Mass #

Multiple Choice

This subatomic particle has a negative charge and is found outside the nucleus.

• Proton

• Neutron

• Electron

Multiple Select

The nucleus is made of these two subatomic particles. (Check all that apply)

• Protons

• Nuetrons

• Electrons

Fill in the Blanks

​Periodic Table of Elements

• ​Created by Dimitri Mendeleev

• ​Organized by ATOMIC NUMBER

  ​

  • ​Why? - Atomic number is the number of protons.

  • This is the only subatomic particle unique to every element!

​GROUPS

​18 Vertical columns of the periodic table.

​

Most tell us the number of valence electrons!

​PERIODS

​7 horizontal rows of the periodic table.

​

Tell us the number of electron shells!

Multiple Choice

How is the periodic table of elements organized?

• By atomic mass

• By atomic number

• By atomic neutrality

• By element symbol

Multiple Choice

Groups are the ________ of the periodic table

• Vertical Columns

• Horizontal Rows

• Only the rows at the bottom

• Only the columns on the far right

Multiple Choice

What element is located at period 2, group 17?

• Oxygen (O)

• Potassium (K)

• Fluorine (F)

• Rutherfordium (Rf)

​Families/Groups

Each family has a specific name .

• ​Families share similar chemical AND physical properties

• ​

• ​Families share the same number of valence electrons (same reactivity)

​​Elements on the periodic table can be grouped into families based on their chemical properties.

​Main Families

• ​Alkali Metals: 1 valence electron, metals, extremely reactive

• ​Alkaline Earth Metals: 2 valence electrons, metals, malleable

• ​Transition Metals: Good conductors of heat and electricity, found freely or in compounds

• ​Halogens: 7 valence electrons, nonmetals, extremely reactive

• ​Noble Gases: 8 valence electrons, nonmetals (gas), NON REACTIVE

  • (Full shell of electrons = happy)

Multiple Choice

Elements in the same family of the periodic table of elements all...

• have the same number of protons.

• share the exact same chemical structure.

• have similar physical characteristics.

• share the same number of neutrons.

Multiple Choice

What family has 7 valence electrons, made of ALL nonmetals, and is extremely reactive?

• Alkali Metals

• Alkaline Earth Metals

• Halogens

• Noble Gases

Multiple Choice

What element will share similar chemical properties with Boron (B)?

• Gallium (Ga)

• Nitrogen (N)

• Neon (Ne)

• Tin (Sn)