Answer:
₁₁A
Explanation:
Atomic radius
As we move from left to right across the periodic table the number of valance electrons in an atom increase. The atomic size tend to decrease in same period of periodic table because the electrons are added with in the same shell. When the electron are added, at the same time protons are also added in the nucleus. The positive charge is going to increase and this charge is greater in effect than the charge of electrons.
This effect lead to the greater nuclear attraction. The electrons are pull towards the nucleus and valance shell get closer to the nucleus. As a result of this greater nuclear attraction atomic radius decreases.
So in given elements consider A₁₁, B₁₂, C₁₃ ans D₁₇ as sodium, magnesium, aluminium and chlorine. This is the third period and as we move form sodium to chlorine atomic radius decreases. That's why sodium has greater size.
As we move down the group atomic radii increased with increase of atomic number. The addition of electron in next level cause the atomic radii to increased. The hold of nucleus on valance shell become weaker because of shielding of electrons thus size of atom increased
Answer:
A. They would have observed a radioactive signal in both the pellet and the liquid.
Answer:
399
Explanation:
Pb(SO4)2 contains 1 atom of Pb, 2 atoms of S and 8 atoms of O. So, atomic mass of Pb(SO4)2 is 207 + 64 + 128 = 399 u. Therefore, molar mass of Pb(SO4)2 is 399 g/mol.HOPE THIS helps. Good Luck
When, it donates electons.
as for example take
NaCl ( sodium chloride)
it's an ionic compund,
that means it is formed by donating or gaining electrons
Na is writen first than, it must be electropositive i.e it has donated electons which made it positive and the clorine gains electron so it's electronegative.
Na is positive because
as we know it's atomic number is 11 that means it has 11 protons and 11 electrons
now, when it donate electon it has, greater number of protons whose change is +ve so the atom becomes overall positively charged ion or cation.
and something same happens in clorine and because it gains one electron and the number of electrons increase in it by 1 whise charge is -ve so, the atom becomes negatively charged ion or anion which has a -1 charge.
The reaction of Mg Cl2 and KOH can be described as a double substitution type of reaction. This means the cations of the reactants are exchanged in places when the products are formed. In this case, the balanced reaction is expressed
MgCl2 (s) + 2KOH (aq) = Mhg (OH)2 (aq) + 2KCl (s)
