Element of Elements

Today’s lesson

● Intro to atoms● Watch fun video● 5 different atomic models - group work● Why are the different models important

zhang.page.link/chem

Alchemy, Father of Chemistry

What is matter made of?

What did Aristotle think?

Everything is made of 4 elements

● Air● Fire ● Water● Earth

What did ancient philosophers do?

● They think about the world● How humans interacts with the world● No experiments to prove or test their theory

Where do theories came from?

● They describe and summarize what happens● Theories change/ evolve over time

What if you break a rock?

Will it become smaller and smaller until you can’t break it anymore?

tomos - cut/ section (Greek)

a-tomos - cannot be cut

Purely philosophical thinking from Ancient Greeks

Atomic chemistry

Atomic models

1. Billiard ball model

2. Plum pudding model

3. Planetary model

4. Atomic model

5. Electron cloud model

Atomic models

1. Billiard ball model - building simple atomic models

2. Plum pudding model - yummy

3. Planetary model -

4. Atomic model - used to explain bonding

5. Electron cloud model - grade 12 +

Billiard ball model

● John Dalton● Particle model cannot explain everything

○ i.e. electrolysis of water● Element only contains one kind of particle that cannot be broken

down further● Compounds are made up of two or more elements chemically

combined together● Each of the same particles have identical mass● Atoms are shaped like solid spheres

Dalton’s atomic theory

Plum pudding model

● J J Thomson● Experimented with cathode ray tube● Discovered there are particles smaller than the atom● Positive and negative charges in an atom● Negative charges sticks to positive charges like raisins on a bun

Planetary model

● Ernest Rutherford● Did his test with a alpha particle generator and a thin gold foil● Atoms is mostly empty space, filled by electrons● Most of the mass is at the center of the atom

Atomic model

● Niels Bohr (worked with Rutherford)● Similar to planetary model, except electron move around in fixed

pathways or electron shells● Energy level can be determined, but not exact position

Electron cloud model

● Work of chemists and physicists ● Electron have distinct energy levels● You know where certain electron are most likely to be found, but

never its exact position● Electron is both a wave and a particle

Element symbols

Why do we use abbreviations?

So Lady Gaga can make songs