Answer:
Rb
Explanation:
Second ionization energy is the energy required for the removal of the second loosely bonded valence electron from an isolated gaseous atom.
The given elements:
Rb , Sr, Y and Zr
These are the elements of the fifth period.
The electronic configuration of Rb -
The electronic configuration of Sr -
The electronic configuration of Y -
The electronic configuration of Zr -
<u>When one electron is removed from Rb, the cation attains the noble gas configuration due to which the removal of second electron from Rb is very very difficult. Thus, Rb has the largest second ionization energy.</u>
The values of the second ionization of these elements are:
Rb = 2633 kJ/mol
Sr = 1064.2 kJ/mol
Y = 1180 kJ/mol
Zr = 1270 kJ/mol
Answer:
90g
Explanation:
I hope this helps plz give brainliest ! :D
<h2>
Which source would be most reliable for gathering experimental results related to a new compound’s molecular mass : A textbook that lists molecular masses of similar compounds</h2>
Explanation:
Atom:
It is a smallest particle of an element which may as may not have independent existence.
The are very small in size.
Their size is measured in unit nm (nanometer)
1nm – 10⁻⁹ m.
hydrogen atom is smallest of all size is only 10⁻¹⁰ nm
Atoms are represented by symbols (given by berzelius )
Atomic mass of element-
Active atomic mass of atom can’t be measured but relative atomic mass can be known.
I.e. relative atomic mass of an atom of element is defined as average relative mass of atom as compared with atom of 612c taken as 12u.
Atomic mass – no. Of times one atom of he element is heavier then 1/12th of c atom.
Molecule
It is smallest particle of an element or compound which is able to exist independently.
Some element exist as
Diatomic molecuel eq:- O₂
Triatomic molecule eq:- O₃
¬
So,
Atomicity – is no. of atoms in a molecule of an element.
Some more examples:- phosphorous P4 (tetra atomic)
sulphur S8 (poly-atomic)
nitrogen N2 (diatomic)
Molecular mass
It is the mass of molecule that is obtained by adding masses of atoms multiplied with number of atoms of each type .
Ba(OH)2 is an basic solution. It has more OH- ions than H+ ions. pOH should be calculated to find out its pH
The reaction is
Ba(OH)2 ⇒ Ba2+ (aq) + 2 OH-(aq)
One mole barium hydroxide releases 2 moles hydroxide ions.
Use that ratio to calculate molarity (M) of OH- ions [OH-]. The ratio is 1:2.
0.10 M Ba(OH)2 release 2*0.10 M= 0.02 M OH- ions
[OH-]= 0.02
pOH= - log [OH-] = - log 0.02 = 1.7
Thats not the answer! We found pOH of the solution before titration.
pH and pOH relationship is shown by formula of pH+pOH= 14
pH= 14-pOH
pH= 14-1.7= 12.3