Lanthanide Lanthanoid, also called Lanthanide
Answer:
d) PO4^3-, HPO4^2-
Explanation:
Basically, an acid and a base which differs only by the presence or absence of proton (hydrogen ion) are called a conjugate acid-base pair.
a) HI, I
This is incorrect. For the acid, HI the conjugate base is I⁻ ion.
b) HCHO2, SO4^2-
This is incorrect, there's no relationship between both entities.
c) CO3^2-, HCI
This is incorrect, there's no relationship between both entities.
d) PO4^3-, HPO4^2-
This is correct. The difference between both entities is the Hydrogen ion. This is the conjugate acid-base pair
The compound nitrogen have most positive oxidation state is NO₂. The correct option is b.
<h3>What is oxidation state?</h3>
The total number of electrons gained or lost by an atom in order to form a chemical bond with another atom.
The charge on an ion is equal to the sum of the oxidation states of all the atoms in the ion. A substance's more electronegative elements are given a negative oxidation state.
A positive oxidation state is assigned to the less electronegative element.
Thus, the correct option is b, NO₂.
Learn more about oxidation state
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Answer:
The density of Lithium β is 0.5798 g/cm³
Explanation:
For a face centered cubic (FCC) structure, there are total number of 4 atoms in the unit cell.
we need to calculate the mass of these atoms because density is mass per unit volume.
Atomic mass of Lithium is 6.94 g/mol
Then we calculate the mass of four atoms;

⇒next, we estimate the volume of the unit cell in cubic centimeter
given the edge length or lattice constant a = 0.43nm
a = 0.43nm = 0.43 X 10⁻⁹ m = 0.43 X 10⁻⁹ X 10² cm = 4.3 X 10⁻⁸cm
Volume of the unit cell = a³ = (4.3 X 10⁻⁸cm)³ = 7.9507 X 10⁻²³ cm³
⇒Finally, we calculate the density of Lithium β
Density = mass/volume
Density = (4.6097 X 10⁻²³ g)/(7.9507 X 10⁻²³ cm³)
Density = 0.5798 g/cm³
Answer:
Polar Covalent
Explanation:
Chlorine and Fluorine are both halogens. They are in group VII.
The Pauling's electronegativity value of these elements are:
F = 4.0
Cl = 3.0
Electronegativity of an element is a property that combines the ability of its atom to lose and gain electrons. It can be used to predict bond type.
For heteronuclear molecules where the electronegativity difference is between 0.5 and 1.7 there will not be an equal sharing of the electron pair between the atoms involved.
The bond that results is a Polar Covalent bond.
When the electronegativity difference is zero or less than 0.5, a non-polar covalent bond forms. There would be an equal sharing of the electron pair donated.