Alkaline earth metal are the elements present in II group in the periodic table and are known as 'Metals' and have a charge of +2.
Alkaline earth metals - Be , Mg Ca, Sr , Ba, Ra
Halogens are present in VII A group in the periodic table and are 'Non-metals' and have a charge of -1.
Halogens - F, Cl, Br, I, At
When Alkaline earth metal (metals) combine with Halogens (non-metals) the compound formed will be ionic compound and the formula of the compound will be based on the charges of the element.
When we write the formula of the ionic compound the charges of the elements get criss crossed.
For example - Mg (Alkaline earth metal) have a charge of +2 and Cl (Halogen) have a charge of -1 and when they combine to form the formula their charges get criss crossed and we will get 
or 
When an alkaline earth metal, A, reacts with a halogen, X, the formula of the Ionic compound formed should be 
Answer:
a. V = 1000 mL
b. Denisty = 0.022 g/mL
Explanation:
a.
First we need to convert the volume of the Osmium into mL. For that purpose we are given the conversion unit as:
1 mL = 0.1 cL
Hence, the given volume of Osmium will be:
V = Volume of Osmium = 100 cL = (100 cL)(1 mL/0.1 cL) = 1000 mL
<u>V = 1000 mL</u>
b.
The density of Osmium is given by the following formula:
Density = mass/Volume
Denisty = 22 g/1000 mL
<u>Denisty = 0.022 g/mL</u>
<span>The high-energy electron travels down an electron transport chain, losing energy as it goes.
Some of the released energy drives pumping of </span><span><span>\text H^+<span>H<span><span>+</span><span></span></span></span></span>H, start superscript, plus, end superscript</span><span> ions from the stroma into the thylakoid interior, building a gradient.
</span><span><span>H^+<span>H<span><span>+</span><span></span></span></span></span>H, start superscript, plus, end superscript</span><span> ions from the splitting of water also add to the gradient.
</span><span><span> H^+<span>H<span><span>+</span><span></span></span></span></span>H, start superscript, plus, end superscript</span><span> ions flow down their gradient and into the stroma, they pass through ATP synthase, driving ATP production in a process known as </span>chemiosmosis<span>.</span>
Ductility - a materials ability to stretch, ie if you pull it apart does it stretch to a wire.
density - ratio of volume to mass
conductivity - materials ability to conduct a current.
hopefully with these definitions you can figure out the answer.
