Atomic Structure

Mr. Rana9/20/12

Bell RingerMake sure you are in your assigned seat, otherwise you will be marked absent. Bell ringer is on page 13 of the packet at the front start working on it.Have your homework 6 out.

1.1c - Students will describe the subatomic components of an atom (protons, neutrons, and electrons), their charges, and their locations.

All matter is composed of atoms. All atoms are composed of three subatomic particles: protons, neutrons, & electrons.

Protons and neutrons are concentrated in the center of the atom, called the nucleus.Electrons orbit the nucleus in a large, diffuse cloud.

Subatomic Particle relative mass relative charge

proton 1 +1

neutron 1 0

electron 1/1836 -1

Practice Problems

1. Which of the following subatomic particles can be found inside the nucleus of an atom?

A. electrons onlyB. neutrons onlyC. protons and neutronsD. protons, neutrons, and electrons

Practice Problems

1. Which of the following subatomic particles can be found inside the nucleus of an atom?

A. electrons onlyB. neutrons onlyC. protons and neutronsD. protons, neutrons, and electrons

2. What are the charges of the following subatomic particles:

A. Protons Charge:_________B. Neutrons Charge:_________C. Electrons Charge:_________

2. What are the charges of the following subatomic particles:

A. Protons Charge:_________. B. Neutrons Charge:_________

C. Electrons Charge:_________

3. Classify each of the following subatomic particles as heavy or light (circle).

A. Protons Heavy or LightB. Neutrons Heavy or LightC. Electrons Heavy or Light

3. Classify each of the following subatomic particles as heavy or light (circle).

A. Protons Heavy or LightB. Neutrons Heavy or LightC. Electrons Heavy or Light

1.1d – Students will understand the relationship between atomic number and the number of protons. Students will understand the relationship between the atomic mass and the number of protons and neutrons (Group 3).

The atomic number is the number of protons in the nucleus of that atom

If the atom is neutral, the atomic number is also the number of electrons in that atom.

The periodic table is arranged by increasing atomic mass and increasing atomic number as you go left to right.

Because protons and neutrons make up most of the mass of the atom, the atomic mass is the sum of the total number of protons and neutrons.

Practice Problems

1. How many protons, neutrons, and electrons does Hydrogen have?

2. How many protons, neutrons, and electrons does Carbon have?

3. Cobalt has an atomic mass of 59 and an atomic number of 27. What does this information reveal about most cobalt atoms?

A. They contain more neutrons than protons.B. They naturally have a net negative charge.C. They attract protons more strongly than electrons.

D. They form ions with a charge of +27 in compounds.

1.1e – Students will understand that most of the mass of an atom is found in the nucleus.

In the Rutherford gold foil experiment, positively charged alpha particles were shot toward a very thin gold foil. Most of the alpha particles passed through the foil, but approximately 1/8000 were deflected.

• Rutherford’s gold foil experiment proved that the atom is mostly empty space, with a concentrated core of positive charge in the nucleus.

• Rutherford also concluded most of the mass of the atom is concentrated in the nucleus.

Practice Problems:

1. Why did Rutherford conclude that the atom is mostly empty space?

2. Why did Rutherford conclude that protons were found concentrated in the center of the atom?

3. Neutrons were discovered at a later time. What do you think the purpose of neutrons are?

4. The arrangement of particles in atoms is similar for all elements.

A. Draw a model of the structure of a helium (He) atom. Include and label all the major components of the atom.

B. Describe where most of the mass is located in the helium atom.

C. Describe where the charges are distributed in the helium atom.