Answer:
the size of Ca is the greatest ,then Mg is the greater on size than Be
Explanation:
if you make the electron configuration for each of the elements, what is the main difference u gonna see ?
Be 4 1s2/2s2
Mg 12 1s2 /2s2 2p6/3s2
Ca 20 1s2 /2s2 2p6/3s2 3p6 3d/4s2
see that all the elements are in the same group but are in different period
u gonna see the last electron valance shell in Ca are too far from its nucleus but in Be the last electrons are too close and more attracted to the atom's nucleus , so the size of Ca is the biggest then Mg then Be
Balancing of chemical equation is essential because of the law of conservation of mass, which states that the mass of a system can not be created or removed.
The second equation is balanced
This is because the number of elements of each atom in the product side equal the number of elements of each atom on the reactant side.
The first equation is not balanced
This is because there is 1 molecule of 
on reactant side as compared to 3 molecules of
To balance the equation we add a coefficient of 3 on sulphuric acid (
) and a coefficient of 3 on hydrogen (
)
Answer:C2H6N
Explanation:
Putrescine formula is C4H12N2
Assuming 100g sample is present
The percent changes to grams and it is converted to moles by dividing it with the atomic masses.
C= 54.50g/12 = 4.541moles
H = 13.73g/1 = 13.73moles
N= 31.77g/14 = 2.269moles
Divide through with the smallest moles value.
C= 4.541/2.269 = 2
H= 13.73/2.269=6
N= 2.269/2.269=1
Therefore the empirical formula is
C2H6N
