Answer:
The vertical columns are called groups.
Explanation:
Periodic table consist of vertical columns and horizontal rows.
Vertical columns are called groups while horizontal rows are called periods.
There are seven periods and 18 groups in periodic table.
The elements in same group have similar properties and can react in a similar way.
The elements in same group have same number of valance electrons that's why their reactivity is same.
Consider the example of alkaline earth metals. They are present in group two and have same number of valance electrons (two valance electrons).
They react with oxygen and form oxide.
2Ba + O₂ → 2BaO
2Mg + O₂ → 2MgO
2Ca + O₂ → 2CaO
this oxide form hydroxide when react with water,
BaO + H₂O → Ba(OH)₂
MgO + H₂O → Mg(OH)₂
CaO + H₂O → Ca(OH)₂
With sulfur,
Mg + S → MgS
Ca + S → CaS
Ba + S → BaS
Answer: 15.850
Explanation:
The conversion used from liters to gallons is:
1 L = 0.264172 gallon
The conversion used from sec to min is:
60 sec = 1 min
1 sec =
We are asked: liters/sec = gallons/min
Therefore, to convert from liters/second to gallons/minute, multiply the number of liters/second by 15.850.
Explanation:
The chemical formula magnesium sulfide written as MgS and NOT 
because charge on magnesium ion is +2 and charge on sulfide ion is -2.
Therefore, these charges will cancel out each other as we write the formula in simplest crisscross method.
Also, the numbers in a chemical formula display the total number of atoms attached with each other or central atom.
For example, in 
there are two chlorine atoms attached to one calcium atom.
Therefore, 
denotes one sulfur atom is attached to magnesium atom. Hence, we do not write the formula of magnesium sulfide as because this shows two magnesium atoms are attached to two sulfur atoms which is not true.
Answer:
Plastic polymers
Explanation:
Plastic polymers are usually made up of synthetic and semi-synthetic polymers such as polyethylene, polystyrene etc.
Plastic polymers have a unique property called malleability. Malleability is the ability of a substance to be moulded into different sizes and shapes.
When hear is applied plastics gets soft and can be molded into different forms and then it becomes hardened after exposure to air(dried).
The plastic polymers are usually very cheap to produce in large quantities which is why it is very common in industries.
2 is the correct answer because with 2O2 molecules it balances the chemical equation.
Hope that helps
