Lanthanide belongs to period 6, and actinides belongs to period 7
The mass number is the summation of number of proton and neutron present in a nucleus of an atom. For the neutral atom the number of positive charge (number of proton) must be equal to the number of electrons. The number of electrons present in an atom is the atomic number of the atom. The standard way to express the mass number (a) and atomic number (m) of a atom (say X) is 
. Now for silicon number of electron or atomic number is 14. And the mass number (a) given 29. Thus the expression nucleus of silicon will be 
Answer:
the equation is balanced because there are 8 atoms of carbon, 26 atoms of oxygen, and 20 atoms of hydrogen. on each side of the equation.
PLEASE MARK BRAINLIEST
Answer : The Bronsted-Lowry theory was not against the Arrhenius theory, rather it was just a modification to the previous theory of acids and bases. Hydroxide ions are considered as bases because they have the tendency to accept hydrogen ions from acids and form water.
An acid was the one which produces hydrogen ions in solution because it reacts with the water molecules by giving a proton to them.
In a nutshell, he described bases as hydrogen acceptor and acids as hydrogen donors.
Answer:
48.049 kJ or 48049 J
Explanation:
Hello again.
So we know the formula 
. c is the heat capacity but this time, it is not given. However, water has a very well known heat capacity which is 4.184 J/(g°C). This is in fact the number we refer to a calorie which is the amount of energy you burn that can raise the temperature of 1g of water by 1°C. So, plugging in values, you get the above. But double check if I am wrong.
