The AtomContains 3 subatomic particles:

Neutron – nucleus particle with no charge. - can vary within an element - ISOTOPES.

Proton – nucleus particle with a positive charge. Electrons – negative particles move in specific orbits.

- e- jump/drop orbits releasing energy.

- same # of positive and negative charges = neutral.

ELEMENT - a fundamental pure substance that cannot be broken down into simpler parts.

Atoms contain 3 subatomic particles:Neutron (no) – nucleus particle with no charge. Proton (p+) – nucleus particle with positive charge. Electrons (e-) – negative particles in orbits.

Bohr Diagrams and

Atomic Information

• Describe the terms atomic number and atomic mass number.

• State the charge, location, and mass of the subatomic particles.

• Draw the Bohr model of atoms.

Key WordsBohr model Periodic tableAtomic mass Atomic NumberValence electrons

Element Modern Symbols Alchemist Symbols Dalton Symbols

Antimony Sb  

Arsenic As  

Bismuth Bi  

Carbon C  

Copper Cu

Gold Au

Iron Fe

Lead Pb  

Mercury Hg

Silver Ag

Sulpher S

Tin Sn    

Zinc Zn    

Symbols originated from a Greek or Latin nameAll these new elements needed names and symbols.

Neutrons

Protons

A proton has a mass of 1 atomic mass unit (μ).

Since the neutron is the same size, it is also 1 μ.

electrons

Electrons are considered zero mass (too small).

All unreacted atoms are neutral - number of protons and electrons are the same.

+-

The atomic mass is equal to the total mass of the protons and neutrons in the nucleus

The units of Atomic mass are amu OR μ.

Heavier elements have a bigger nucleus – more protons (and neutrons).

No TWO elements have the same number of protons.

The number of protons in an element does NOT change.

Proton number is used to identify an element.

The number of protons in the nucleus of an element is called the atomic number.

Number of Protons Atomic Number

Number of Neutrons Atomic Mass – Atomic Number

Number of Electrons Number of protons (Atomic Number)

4 – 2 = 2

Sulfur (S)

How many protons are there in one atom of Sulfur?Atomic number 16 - 16 p+

How many electrons in one atom of Sulfur?

How many neutrons in one atom of Sulfur?

How many protons in 3 atoms of Sulfur?

Atoms are neutral - 16 e-

Atomic mass 32 32-16 = 16 no

3 x 16 = 48 p+

Potassium (K)

How many protons in one atom of Potassium?

Atomic number is 19 – 19 p +

How many electrons in one atom of Potassium?

How many neutrons in one atom of Potassium?

How many protons in 10 atoms of Potassium?

Atoms are neutral – 19 e -

At mass – At number 39 – 19 = 20 no

10 x 19 p + = 190 p +

Atomic Informationand

Bohr Diagrams

Electrons begin filling the closest energy level to the nucleus first.

All electrons found in the outer orbit are called VALENCE electrons.

Lithium has an atomic number of 3.

Lithium has ONE Valence electron.

Drawing a Complete Bohr Atom

1. Determine the number of no, p+, e- in the atom.2. Draw the nucleus.3. Label the #of protons and neutrons in the nucleus4. Add orbits and fill with the appropriate # of e-.

7p+

7no

Nitrogen (N)

p+ : 7

no : 14 – 7 = 7

e- : 7

11p+

12no

Sodium (Na)

p+ : 11

no : 23 – 11 = 12

e- : 11

• Atom is made of protons, neutrons and electrons.

• Electrons travel in orbits or energy levels around the nucleus (outer orbit – valence)

• Atomic number is equal to the number of protons.

• Atoms are neutral - number of protons and electrons is the same.

• Atomic mass is the protons plus the neutrons