Answer:
Ba
Explanation:
Magnesium is the element of second group and third period. The electronic configuration of magnesium is - 2, 8, 2 or 
There are 2 valence electrons of magnesium.
Fluorine is the element of seventeenth group and second period. The electronic configuration of fluorine is - 2, 7 or 
There is 1 valence electron of fluorine.
They will combine and form 
<u>The same type of compound is formed by the other members of the group 2 since they will have 2 valence electron.</u>
Group 2 includes:- beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra).
Hence, correct options is:- Ba
Answer:
900g
Explanation:
Given parameters:
Number of moles of Sc = 20moles
Unknown:
Mass of Sc = ?
Solution:
To find the mass of the scandium given, we use the expression below:
Mass = Number of moles x molar mass
Molar mass of Sc = 45g/mol
So;
Mass of Sc = 20 x 45 = 900g
Answer:
9Be
4
Explanation:
Atomic number = (3+2)-1= 4
Mass number = (6+4)-1 =9
Answer:
The change from a liquid phase to a gaseous phase occurs when the vapor pressure of the liquid is equal to the atmospheric pressure exerted on the liquid.
Explanation:
Boiling is a physical change and molecules are not chemically altered during the process.
Answer:
Chemical reaction are irreversible. Some of the example of chemical reaction are cooking, rusting, and burning. During a chemical reaction, the composition of substances changes and the particles rearrange to form a new substance. The new substance formed after chemical reaction of substance has different physical and chemical properties.
When a chemical reaction occur, the atoms or molecules of the substances change its physical and chemical properties such as while cooking of vegetable, the molecules of vegetable undergo changes in their properties and form a new substance which is different from the earlier.
