4.1 atoms and elements

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• Middelbare school
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• Leerjaar 3

Chapter 4 Building blocks of everything

4.1 Atoms and Elements

- What is an atom?

- Atomic models

- Buildingblocks of an atom

Dalton's Atomic Theory

- Atoms are small indivisible particles

- Each element is made up of 1 type of atom

- Atoms have unique properties and their own mass

Dalton's Atomic Theory

- Atoms retain their identity after a chemical reaction

- Chemical reaction: regrouping atoms

Which of the understanding pictures shows a atom and which shows a molecule?

Atom

Molecule

Building blocks of atoms

- Protons

- Neutrons 

- Electrons

Rutherford's Atomic model

- Nucleus: protons and neutrons

- Electron cloud: electrons fly in circles around the nucleus

Properties of protons, neutrons and elektrons

	Mass	Charge	Place
Proton	1 u	+	Core
Neutron	1 u	0	Core
Electrons	0,00054 u (rounded to 0 u)	-	Electron Cloud

Rules for building atoms

- Atomic number: number of protons = number of electrons

- The atomic number is at the top of the periodic table

- Mass number = number of protons + number of neutrons

What is the atomic number of nitrogen?

1. 14
2. 12
3. 6
4. 7

What is the mass number of nitrogen?

1. 14
2. 12
3. 6
4. 7

How many electrons does a nitrogen atom contain?

1. 14
2. 12
3. 6
4. 7

Bohr 's Atomic Model

- Electrons move in circular shells around the nucleus

- K-shell: 2 electrons

- L-shell: 8 electrons

- M-shell: 8 electrons

How many electrons are there in the K, L and M shell of an oxygen atom?

1. K=2, L=3, M=3
2. K=0, L=4, M=4
3. K=2, L=6, M=0
4. K=2, L=0, M=6

summarized:

- There are 3 atomic models: Dalton, Rutherford and Bohr

- Atoms are made up of protons (charge +, mass 1u, neutrons (charge 0, mass 1u) and electrons (charge -, mass 0u)

Homework:

Learnbeat 4.1 assignments 1,2,3 and 7