The Atom Chapter 11 Section 2

Atoms

An atom is so small… A penny contains 2 x 10 22 atoms Or 20,000,000,000,000,000, 000,000 atoms!

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atoms

– the smallest particles into which an element can be divided and will remain the same substance – make up elements – often called the building blocks of matter It would take a stack of 50,000 aluminum atoms to equal the thickness of a sheet of aluminum foil!

Parts of an Atom

• Even though an atom is tiny, it consists of even smaller parts/particles:

Nucleus BrainPOP Atom Electron Cloud

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nucleus

– small, dense, positively charged center of the atom • contains most of the atom’s mass •

electron cloud

– region around the nucleus of an atom where electrons are found • contains most of the atom’s mass • Particles inside Nucleus: 1. Proton 2. Neutron the • Particles outside Nucleus: 3. Electron the

Inside the Nucleus: Protons

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protons

nucleus - positively charged particles of the – All are identical – Each proton has an amu (atomic mass unit) of 1 • Write/Say as: 1 amu

Inside the Nucleus: Neutrons

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neutrons

charge - particles of the nucleus that have no – All neutrons are identical – While neutrons are a bit larger than protons, they are not enough bigger to have a larger amu. • Neutron = 1amu

Outside the Nucleus: Electrons

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electrons

atoms - negatively charged particles in – around the nucleus within electron clouds • 1 st Level: 2 Electrons • 2 nd • 3 rd Level: 8 Electrons Level: 18 Electrons – charges of protons and electrons are opposite but equal in size – mass 1 proton ≈ 1800 electrons! • Electrons are so small the mass is usually considered to be zero!

2 8 18

Building Atoms

Let’s build the simplest atom…the hydrogen (H) atom Proton Electron

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Can we build bigger atoms?

Sure! Try this on your own paper… • A carbon atom has 6 protons, 6 neutrons, and 6 electrons or • An oxygen atom that has 8 protons, 9 neutrons, and 8 electrons

IN Activity: Summarize 3 – 2 – 1 Review!

• On your output page: – 3 Particles in an Atom – 2 Main Parts of an Atom – 1 The Building Blocks of Matter