Electrostatic Force Opposites Attract Like Charges Repel

Q1Q1 Q1Q1 Q2Q2 Q1Q1 Q1Q1 Q2Q2 Q = Charge r = distance K = constant The greater the charge the greater the force. The closer the charged particles are, the stronger the electrostatic force.

e -1 p +1 r=1 e -1 p +1 r=2 e -1 p +1 r=3

e -1 p +1 r=1 e -1 p +1 r=2 e -1 p +1 r=3 If you double the charge you double the force. If you triple the charge you triple the force. If you double the distance you reduce the force by 4 times as much. If you triple the distance you reduce the force by 9x as much.

1.Opposite Charges ________________. Like charges ________________. If charge increases then force ____________. If distance increases then force _________. 1.Explain the inverse square law and its importance. 2.If the value of the charge on an object quadruples, what happens to the value of the electrostatic force? 3.If two charges separated by 1 nanometer are moved twice as far apart, what happens to the value of the electrostatic force between them? 4.If the distance between two charges is cut in half, what happens to the value of the force? 5.If you double both the total charge of an object and the distance between those two objects, what happens to the value of the electrostatic force? 6.Considering the actual charge of a proton is (35)×10 −19 C and an electron is (35)×10 −19 C what would be the electrostatic force between them at a distance of 1 nanometer (1.0 × meters). Assume K = ke = ×10 9 N·m 2 /C 2.

Nuclear Charge Increases Total electric charge in a nucleus. It is equal to the number of protons. The Nucleus is what attracts electrons.

1 H Hydrogen 1 3 Li Lithium 7 11 Na Sodium 23

1 H Hydrogen 1 3 Li Lithium 7 11 Na Sodium 23

1 H Hydrogen 1 3 Li Lithium 7 11 Na Sodium 23

1 H Hydrogen 1 3 Li Lithium 7 11 Na Sodium 23

1 H Hydrogen 1 3 Li Lithium 7 11 Na Sodium 23 As you go down a group or column in the periodic table the number of energy levels increases.

1 H Hydrogen 1 3 Li Lithium 7 11 Na Sodium 23 As you go down a group or column in the periodic table the number of energy levels increases.

1 H Hydrogen 1 3 Li Lithium 7 11 Na Sodium 23

Nuclear Charge Increases Atomic Size Increase

5 B Boron 1 3 Li Lithium 7 4 Be Beryllium 23

5 B Boron 1 3 Li Lithium 7 4 Be Beryllium 23

5 B Boron 1 3 Li Lithium 7 4 Be Beryllium 23

5 B Boron 1 3 Li Lithium 7 4 Be Beryllium 23

5 B Boron 11 3 Li Lithium 7 4 Be Beryllium 9 As you go across a period the number of energy levels remains constant.

Electrons in an atom can shield each other from the pull of the nucleus.

As you go across a period electron shielding is constant. As you go down a group electron shielding increases.

Nuclear Charge Increases Atomic Size IncreaseElectron Shielding Increases Electron Shielding Remains Constant Atomic Size does what????

5 B Boron 11 3 Li Lithium 7 4 Be Beryllium 9 As you go across a period atomic size decreases because the pull of the nucleus (nuclear charge) increases but electron shielding remains constant. The nucleus is able to pull the electrons closer (Coulomb’s law).

Nuclear Charge Increases Atomic Size IncreaseElectron Shielding Increases Electron Shielding Remains Constant Atomic Size Decreases

The energy required to remove the outermost electron from an atom.

As you go across a period 1st ionization energy increases. As you go down a group 1st ionization energy decreases. Additional Electron shielding and increased distance from the nucleus makes removing the outermost electron much easier. Increasing nuclear charge without any additional shielding makes removing the outermost electron more difficult.

Why does the high 1 st ionization energy of the Noble gasses indicate?

Nuclear Charge Increases Atomic Size IncreaseElectron Shielding Increases Electron Shielding Remains Constant Atomic Size Decreases 1 st Ionization Energy Increases 1 st Ionization Energy Decreases

A measure of an atom or group of atom’s tendency to attract electrons

As you go across a period Electronegativity increases. As you go down a group Electronegativity decreases. Additional Electron shielding and increased distance from the nucleus makes adding a new electron more difficult Increasing nuclear charge (pull) without any additional shielding makes makes adding an electron easier.

Fluorine is the most electronegative element. What about the Noble gasses?

Nuclear Charge Increases Atomic Size IncreaseElectron Shielding Increases Electron Shielding Remains Constant Atomic Size Decreases 1 st Ionization Energy Increases 1 st Ionization Energy Decreases Electronegativity Increases Electronegativity decrease

For now we can think of an atom’s tendency to lose or gain electrons as its reactivity. So atoms that lose electrons very easily or have a strong affinity for electrons are considered the most reactive.

Nuclear Charge Increases Atomic Size IncreaseElectron Shielding Increases Electron Shielding Remains Constant Atomic Size Decreases 1 st Ionization Energy Increases 1 st Ionization Energy Decreases Electronegativity Increases Electronegativity decreases Metals: Reactivity decreases Metals: Reactivity IncreaseNonmetals: Reactivity decreases Nonmetals: Reactivity Increases

st Ionization energy is the amount of energy needed to remove the outermost electron in an atom. 2 nd Ionization Energy level is the energy required to remove the next electron. QUESTION: Will sodium have a higher or lower 2 nd Ionization energy compared to its first Ionization energy? Explain this in terms of the inverse square law, Coulomb’s law and electron shielding.