Activity 4.1 – Modeling Atoms, Ions and Compounds
In this activity, you will draw Bohr and Lewis diagrams for ionic and covalent
compounds. Refer back to the notes or animations for assistance; there is
minimal explanation in this assignment.
For your drawings, you have several options for how to submit these:
1) draw on paper, scan and upload.
2) draw on paper, take picture with smartphone and insert into this document
3) draw using computer program and insert into document (likely too complicated
unless you are REALLY good with computers)
***MAKE SURE TO NUMBER YOUR DRAWINGS***
Part 1 – Bohr Models of Atoms, Ions and Compounds
Instructions: atoms and ions
Recall that in a Bohr model, all the electrons are drawn in their shells.
For example, here is a Bohr model of Sodium:
Sodium’s atomic number is 11. This means it has 11 protons
Sodium’s mass is 23 (rounded off), so if you subtract the number of protons from
the mass (23-11) you end up with 12 neutrons.
Since this is an atom, it has the same number of protons as electrons, so 11
electrons. The first shell can hold 2, the next shell 8, the third shell 8 and the
fourth can hold 18
If this was a sodium ION, the number of protons and electrons would NOT be
equal, and the atom has a charge, making it an ion. If you refer to your periodic
table, you will see Sodium as an ion has a charge of 1+. This means a Bohr
model of a sodium ion must have only 10 electrons (recall you CANNOT change
the number of protons) to give it a 1+ charge.
Draw Bohr Diagrams for these atoms or ions
1)
2)
3)
4)
5)
Sodium ion - Na+
Fluorine Ion – FNeon atom – Ne
Lithium Ion – Li+
Beryllium atom - Be
Instructions: Ionic Bohr Compounds
Ionic compounds involve the transfer of electrons from a metal to a non-metal.
To draw a Bohr diagram of these compounds, we:
- Draw each atom
- Tip: draw single electrons facing the other atoms
- Remove the appropriate number of electrons (based on ion charge) from
the metal and give to non metal
- Draw parentheses (square brackets) around each atom
- Put the ion charge of each atom as a superscript to the right of the
parentheses
Example: Beryllium Fluoride
If you are doing a covalent compound, for example OF2, you do not do square
brackets or charges. Instead, just show the outer shell of each atom overlapping
and sharing their electrons.
Draw Bohr Diagrams for the following ionic and covalent compounds:
6) LiF
7) MgF2
8) NaCl
9) F2
10) CH4
Part 2: Lewis Diagrams of Atoms, Ions and Compounds
Recall that Lewis diagrams are much simpler than Bohr diagrams as they only
show the electrons in the outermost shell. These are called the valence
electrons. You do NOT need to draw circles or all the electrons.
For ionic compounds, you still need square brackets and charges as before, but
no circles for the electron shells.
For covalent compounds, rather than showing overlapping orbitals, a stick is
used to represent shared electrons between the atoms.
Ex:
Draw Lewis Diagrams for these atoms or ions
11) Sodium atom - Na
12) Fluorine Ion – F13) Neon atom – Ne
14) Lithium Ion – Li+
15) Beryllium atom – Be
Draw Lewis diagrams for these Ionic and Covalent compounds.
16) LiCl
17) MgCl2
18) NaCl
19) F2
20) CH4