Answer:
1 valence - Alkali Metals: Li Lithium, Na Sodium, K Potassium
2 valence - Alkaline Earth Metals: Be Beryllium, Mg Magnesium, Ca Calcium
3 valence - Non-metals: B Boron, Al Aluminium
4 valence - Non-metals: C Carbon, Si Silicon
5 valence - Non-metals: N Nitrogen, P Phosphorus
6 valence - Non-metals: O Oxygen, S Sulfur, Se Selenium
7 valence - Halogens: F Fluorine, Cl Chlorine, Br Bromine
8 valence - Noble Gases: He Helium, Ne Neon, Ar Argon
There are usually 3 topics used to compare types of radiation:
Ionising ability
Penetrative power
Range in air
Ionising ability
Alpha radiation has strong ionising ability, while beta only has moderate ionisation and gamma is very weakly ionising.
Penetrative power
Alpha particles are weakly penetrating, stopped by paper, while beta particles have stronger penetrating ability, stopped by skin and gamma radiation is very strongly penetrating, stopped only by thick layers of lead.
Range in air
Alpha particles- range of only a few centimetres
Beta - range of up to one meter
Gamma- infinite range in air.
Hope this helps:)
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 
Matter is a slightly archaic word for something with mass, as in the conservation of matter (which must be paired with the conservation of energy to still hold true. Mass can be converted back and forth between energy, so therefore so can matter. Of course relativistic mass is conserved as it's a function of the energy of an object in that reference frame.
Answer:
B
Explanation:
Trust me I've had problems like these
