Answer:
One of the bonds in nitrate is shorter than the other two.
Explanation:
We would firstly need to draw the Lewis structure for nitrate anion. To do this, let's follow the standard steps:
- calculate the total number of valence electrons: five from nitrogen, each oxygen contributes 6, so a total of 18 from oxygen atoms, as well as one from the negative charge, we have a total of 24 valence electrons;
- assign the central atom, usually this is the atom which is single; in this case, we have nitrogen as our central atom;
- assign single bonds to all the terminal atoms (oxygen atoms);
- assign octets to the terminal atoms and calculate the number of electrons assigned;
- the number of electrons assigned is 24, so no lone pairs are present on nitrogen;
- calculate the formal charges: each oxygen has a formal charge of -1 (formal charge is calculated subtracting the sum of lone pair electrons and bonds from the number of valence electrons of that atom); nitrogen has a formal charge of +2;
- nitrogen doesn't have an octet as well, so we'll both minimize its formal charge and make it obtain an octet if we make one double bond N=O.
Therefore, we may have 3 resonance structures, as this double bond might be formed with any of the 3 oxygen atoms.
By definition, double bonds are shorter than single ones, so one of the bonds is shorter than the other two.
Answer:
E = 19.89 × 10⁻¹³ J
Explanation:
Given data:
Wavelength of gamma ray= 1.0× 10⁻¹³ m
Energy of gamma ray = ?
Solution:
Formula:
E = h c/λ
h = plancks constant = 6.63× 10⁻³⁴ js
c = speed of light = 3 ×10⁸ m/s
by putting values,
E = 6.63× 10⁻³⁴ js × 3 ×10⁸ m/s /1.0× 10⁻¹³ m
E = 19.89 × 10⁻²⁶ J.m/ 1.0× 10⁻¹³ m
E = 19.89 × 10⁻¹³ J
2<span> NH3 the ratio between N2 and H2 is </span>1<span> : 3 ... actual moles H2 = 5000 g / </span>2<span> g/mol=2500 so H2 is the limiting reactant</span>
The elements that have the same valence are, mainly, in the same principal groups (principal columns) of the periodic table.
The principal columns are 1, 2, 13, 14, 15, 16, 17 and 18.
For example:
1) the elements with valence 1+ are in the first column:H, Li, Na, K, Rb, Cs, Fr.
2) The elements with valence 2+ are in the second column: Be, Mg, Ca, Sr, Ba, Ra.
3) The elements with valence 2- are in the column 16: O, S, Se, Te, Pb
But also those elements may have other valences: S, Se and Te, have also valences 2, 4 and 6. And Pb have valences 2 and 4.
4) The elements with valences 1-, 1, 3, 5 and 7 are in the column 17: Cl, Br, I, At.
F, the first element of group 16, has valence 1- and 1+
