Science 7 Notes 13 Atoms Proton Describe the Neutron structure of an atom.

Electron Be able to identify Atomic Mass the number of protons, neutrons, Atomic Number and electrons in an atom.

Identify the Structure of an atom: subatomic  Atoms are made of smaller particles called subatomic particles: particles and their charges?  Protons (positive)  Neutrons (neutral)

 Electrons (negative) Where are the subatomic particles located  Protons and neutrons are located in the nucleus (the center of the in an atom? atom).

 Electrons are orbiting the nucleus.

 The particles of opposite charges are attracted to each other, keeping electrons near the nucleus

 The # of electrons = # of protons

Structure of an Atom Subatomic Location Charge Mass Particle Nucleus of Positive 1 amu Proton the atom

Nucleus of Neutral 1 amu Neutron the atom

VERY Negative Basically no Electron quickly mass orbiting the nucleus

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Science 7 Notes 13

What does the atomic number of an atom represent?

How do the atomic numbers compare between different atoms?

If an atom has 12 protons, how Atomic Number: many electrons does it have?  Number of protons in an atom

 Each atom has a different number of protons

 In atoms the number of protons always equals the number of electrons (making the atom neutral)

Below are the nuclei of 3 atoms. Which atoms are shown? Where do you find the atomic 2 Protons = Atomic Number 2 mass of an element on the Helium periodic table?

How do you get the atomic number from this 4 Protons = Atomic Number 4 value? Beryllium

How do you calculate the mass of an atom? 6 Protons = Atomic Number 6 What does the Carbon atomic mass of an atom represent? Mass Number  Mass Number for an atom = number of protons PLUS neutrons  For the Mass of a single atom, round the atomic mass on the periodic table to the nearest whole number

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Science 7 Notes 13 Finding the Number of Neutrons  To Calculate:

How do you Atomic mass (protons + neutrons) determine the - Atomic number (protons only) number of neutrons an atom possesses? Number of neutrons in one atom

Find the following for the aluminum atom:

Atomic number Practice:

Atomic mass 1. Atomic number of carbon______Number of neutrons Number of 2. Atomic mass of carbon______protons

Number of 3. Mass number for a Carbon atom ______electrons 4. Number of neutrons in a carbon atom ______

5. Number of protons in a carbon atom______

6. Number of elections in a carbon atom ______

1. Atomic number of Molybdenum_____

2. Atomic mass of Molybdenum ______

3. Mass number for a Molybdenum atom ______

4. Number of neutrons in a Molybdenum atom ______

5. Number of protons in a Molybdenum atom______

6. Number of elections in a Molybdenum atom ______

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