Period
Group
Explanation:
On the periodic table the numbers 1,2 and 3 can represent either groups or periods.
The periodic table gives the arrangement of elements based on their atomic numbers
- They are divided into vertical columns and horizontal rows
- The vertical columns are the groups whereas the horizontal rows are the periods.
- The vertical columns are made up of elements having the same number of electrons in their outermost shell.
- The horizontal columns are made up of elements having the same number of shell.
- On the periodic table, the groups are numbered 1 - 18
- There are 7 periods on the table.
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Dissolution means to make the compound apart, So when we have ionic compounds like NaI which has metal and non-metal ions, It separates into parts of positive ions and negative ions. After we separate this compound apart we will put the charge of each on above its symbol and then start to balance the equation of the dissolution.
So the dissolution equation of NaI is:
NaI(s) → Na^+(s) + I^-(Aqu)
Answer:
C) 
Explanation:
pH is defined as the negative logarithm of the concentration of hydrogen ions.
Thus,
pH = - log [H⁺]
The expression of the pH of the calculation of weak acid is:-
Where, C is the concentration = 0.5 M
Given, pH = 2.94
Moles = 0.100 moles
Volume = 1.00 L
So, 
C = 0.100 M
Answer:A typical gasoline mixture contains about 150 different hydrocarbons, including butane, pentane, isopentane and the BTEX compounds (benzene, ethylbenzene, toluene, and xylenes). Gasoline also contains chemicals such as lubricants, anti-rust agents and anti-icing agents that are added to improve car performance.
