Chapter 2 - Steven Flashcards
What are ions?
Positvely or negatively charged atoms
If sodium forms Na+, what has it done?
Lost 1 electron to form a full outer shell.
What is an ionic bond?
The strong electrostatic attraction between 2 oppositely charged ions.
How do ionic charges affect ionic bonding?
The greater the charge on an ion, the stronger the ionic bond
What is the relationship between the strength of the ionic bond and the melting/boiling points?
The stronger the ionic bond, the higher the melting/boiling point
What happens to the electrostatic attraction as the ionic radii?
It decreases
Why does electrostatic attraction get weaker with distance?
The ions sit further apart, so there is less electrostatic attraction.
What happens to the ionic radius as you go down a group?
It increases
What happens to the ionic radius as you go across a period?
It decreases
What do dot and cross diagrams show?
Where the electrons in a bond came from
What do ionic compounds form?
Giant Ionic lattice structures
What is a lattice?
A regular structure
What is a giant lattice?
A structure made up of the same basic unit repeated over and over again
Why do ionic compounds form giant lattice structures?
Because each ion is electrostatically attracted in all directions to ions of the opposite charge
As ionic compounds have high melting/boiling points, what does this provide evidence for?
Their strong forces of attraction between positive and negative ions.
What shows that the particles in ionic compounds are charged?
They are often soluble in water but not in non-polar solvents. The ions are pulled apart by polar molecules like water, but not by non-polar molecles
As ionic compounds can’t conduct when solid, but can when molten, what does this tell you?
That they are ions, which are in fixed positions by strong ionic bonds when solid, but are free to move when molten.
Why are ionic compounds brittle?
If you ever tried to pull layers over each other, you’d get negative chlorine ions directly over negative chlorine ions so there would be a very high repulsion, so they are brittle
When you electrolyse a green solution of copper chromate on a piece of wet filter paper, what happens?
The filter turns blue at the cathode (negative) and yellow at the anode (positve).
Copper fromed at the cathode and chromate formed at the anode
What is isoelectronic?
Having the same number of electrons
What is a covalent bond shared by?
2 or more atoms bonded together
If the atoms ends up with 8 electrons in its outer shell, is it stable or unstable?
It’s very stable
What is a bond containing 2 electron pairs called?
A double bond
In covalent molecules, what is the positive nuclei attracted to?
The area of electron density between the 2 nuclei.