Define a cation. How does an atom become
a cation?
Under what circumstances does an atom
become a cation? Why would it do so?
Define an anion. How does an atom become
an anion?
Under what circumstances does an atom
become an anion? Why would it do so?
How does the
formation of a covalent bond help an atom to fill its valence
shell?
Fill in the blanks in the following table, paying special
attention to atomic charge.
Name
Symbol
No. of p+
No. of n0
No. of e–
Overall
Charge
iron-54
5426Fe2+
5
6
5
16
18
–3
79
118
78
barium-137
81
+2
One isotope of a metallic element has
mass number 65 and 35 neutrons in its nucleus. The cation derived
from the isotope has 28 electrons. Write the symbol for this
cation.
One isotope of an alkali metal has
mass number 87 and 50 neutrons in its nucleus. The cation derived
from the isotope has 36 electrons. Write the symbol for this
cation.
One isotope of a non-metallic element has
mass number 81 and 46 neutrons in its nucleus. The anion derived
from the isotope has 36 electrons. Write the symbol for this
anion.
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What is a Group in the periodic
table? What do you know about the valence electrons of the elements in a group?
The elements in a group have similar chemical and physical properties. Remember the video you watched in class about how the alkali metals (Li, Na, K, Rb, and Cs) react when exposed to water. Using what you know about the valence electrons of elements in a group explain
why elements in a group have similar properties.
What is another name for an electron shell? (Look back at the text of the group activity or at your notes).
What is the reason electrons only exist in shells and never between them? Think about quantum energy.
Why do atoms try to have filled shells?
What is the difference in terms of chemical reactivity between an atom with
an unfilled valence shell and one will a filled valence
shell?
What is more reactive, a fluoride ion (F–) with a full valence shell or a fluorine atom (F) with only seven valence electrons? Why?
Based on your knowledge of groups in the
periodic table, predict the likely charges of the following atoms
if they were to form ions by gaining or losing electrons to fill
their valence shell:
Ca Li Cl N Ne Mg SiBa Rb I As Xe Sr Pb
Show the charge of each atom by writing it as a superscript next to the symbol. Underneath each symbol write how many e- are gained or lost.
Draw the Lewis electron dot structure of the electrically neurtral atoms from the
previous problem.
If you draw the Lewis electron dot structure for ions they would all look the same. Why? Think about how many valence electrons an ion has.