## Periodicity

A.

1. Rubidium (Rb)
2. The more electrons there are on one shell the smaller the atomic radius,  That is why for the first family the atomic radius is big. Every period the atomic radius increases in proportion to the last period.
3. a) Cesium (Cs) -> 0.295 nm       b) Tungsten (W) -> o.135      c)Thallium (Tl) -> 0.180       d) Radon (Rn) -> 0.140
4.  Group one contains the largest elements.

B.

1. The amount of energy needed to remove the looses electrons.        a) By period it increases until it gets to the noble gases, and then the next element decreases drastically, because the valence shell is not complete. By family it decreases one by one.       b) Helium (He).
2. a)[Ne] 3s2 3p5             b) The last electron, the electron configuration would look like this: [Ne] 3s2 3p4.
3. For metals the ionization energy is closer in between each element, and for the nonmetals the ionization energy varies drastically. Metals tend to have lower ionization energy than nonmetals.

C.

1. Within a period the melting point usually increases until it reaches the fourth group, after this point the melting point decreases, however for the metals this changes.
2. The fourth group.
3. Carbon could be a reasonable change for Tungsten, because it has a very high melting point.

D.

1. By period we can see that it increases then decreases and the increases and finally decreases one last time when it reaches the noble gas. This is visible on the graph.
2. The densities a very similar if we look at their group and density, meaning Berium has a similar density to Magnesium.
3. The metals generally have a larger density than the main group, with some metals having more than double the density of the main group.
4. Aluminum and Magnesium are more suitable for airplane parts, because they are less dense than iron which is almost twice their density.

E.

1. Within period, the electronegativity increases drastically.
2. Within group, the electronegativity decreases slowly.

## Flame Test Activity

Different metals absorb the energy from the flames and emit different colours.

1. $LiNO_{3}$

2. $Cu(NO_{3})_{2}$

3. $KNO_{3}$

4. $Sr(NO_{3})_{2}$

5. $Zn(NO_{3})_{2}$

6. $Ca(NO_{3})_{2}$

## Molarity of 10g of NaCl in 200ml of Water

1.
Add ~10.0g of NaCl to solution
2.
Add water to dissolve (& get off the sides)
3.
Fill up to base of neck
4.
Top up with water bottle
5.
Calculate the concentration of a [NaCl] solution with 10.0g and 200ml of $H_{2}O$