BellringerWrite down 5 things you know about atoms.

Use chapter 4 if you need help remembering!

BellringerUse your notes to answer the following

1. What is all matter made of?

2. What is the nucleus of an atom?

3. What two subatomic particles are located in the nucleus of an atom?

4. Which subatomic particle gives an element its identity?

5. An element’s atomic number tells the # of ____ in an atom.

6. What is an isotope? Give an example.

Notes: Atoms

I. Matter: Building block of universe.

• All matter is composed of atoms.

• Energy is not matter (ex. Heat, light, electricity, sound)

II. History of atom- see timeline p.114-115

III. Atoms can be broken down into subatomic particle

Subatomic Particles

1. Protons: – Found in the nucleus of atom– Positively charged – Give element its identity– # of protons is equal to the atomic # of each

element on periodic table.– ex. Carbon– Silver– Iron

BellringerUse your notes to

answer the following.

1. What is the charge of the nucleus of an atom?

2. What is the overall charge of an atom?

3. Fill in the table to the side for protons, neutrons, and electrons:

Mass of Particle

Charge Location

2. Neutrons: – Found in the nucleus of atom– No charge (neutral)– # of neutron in an atom can be calculated

by formula. Mass # - # of protons– Isotopes: atoms of the same element but

with different # of neutrons.

Nucleus: makes up most of the mass of the atom, but takes up very little space.

– Contains protons and neutrons– Positively charged

3. Electrons: • Found outside the nucleus. Orbits nucleus.• Have very small mass• Have a negative charge• # of electrons is equal to the # of protons.

• Overall charge of an atom is neutral. (No charge)

• Mass #: Mass of nucleus of an atom1. Calculated by adding protons + neutrons

2. Mass # is measured in amu: Atomic mass units.

– Atomic Mass: average mass of protons and neutrons including isotopes.

– ex.