Download presentation
Presentation is loading. Please wait.
1
Lewis Structures and Ions Do Now:
Answer the following questions: How do you determine the # of valence electrons for an atom? How many valence electrons do each of the following atoms contain? Potassium: Sulfur: Silicon: Calcium:
2
Write the # of valence electrons and the dot diagram for each element: 1. Li S 3. Ba 4. Sn At Si Li S Ba Sn At Si 1 6 2 4 7
3
Ions Cation Atom Anion
4
Ion- Atom which either gain or lose electrons
to become more stable to become ISOELECTRONIC(iso means same) - same number of electrons as the noble gases. OCTET RULE: atoms will gain or lose electrons to have full shells(8 electrons in the outermost shell except He)
5
Fluorine gains an electron and becomes negatively charged
F + e- F-
6
Sodium loses an electron and becomes positively charged
Na Na+ + e-
7
Quick Activity- Atom charges and Ions
PART I- CATION: LITHIUM: For the atom Lithium : How many Protons and Electrons does this atom contain? For each Proton take a + paper, for each electron take a – paper. What charge does the atom have? To become isoelectronic with Helium Lithium will lose one electron. What charge does Lithium have now?
8
Quick Activity- Atom charges and Ions
PART II- ANION: OXYGEN: For the atom Oxygen : How many Protons and Electrons does this atom contain? For each Proton take a + paper, for each electron take a – paper. What charge does the atom have? To become isoelectronic with Neon Oxygen will gain two electrons. What charge does Oxygen have now?
9
PART III- Mixed practice: Fill in the table below for each element
10
Use your periodic table to help!
12
Smaller than parent element Larger than parent element
Cation Anion Positive ion Negative ion Lose their valence electrons Gain valence electrons From atoms with less than 4 valence electrons From atoms with more than 4 valence electrons Example: Mg Mg Mg2+ + 2e- Example: Cl Cl + e- Cl- Smaller than parent element (less electrons, same protons) Larger than parent element (more electrons, same protons)
13
Size difference… Cation is smaller than parent element because:
Same number of protons (+) Lesser number of energy shells. Anion is larger than parent element because: More electrons and more shielding by inner electrons
14
Ion formation
Similar presentations
© 2024 SlidePlayer.com Inc.
All rights reserved.