Answer:
A. Metallic bond
Explanation:
Think about it: copper and tin are both common metals. That's how we know it's a metallic bond!
Why not B: Covalent bonds are between two nonmetals.
Why not C: Ionic bonds are between a nonmetal and a metal.
Why not D: Paired bond isn't a common phrase in chemistry.
Answer:
it is a viral disease . it is infected by one person to other .
Answer:
Explanation:
We can only talk about resonance hybrid for a compound in which more than one structure is possible based on its observed chemical properties.
There are compounds whose chemical properties can not be satisfactorily explained on the basis of a single chemical structure. In the case of such compounds, we invoke the idea of resonance.
A resonance hybrid is a single structure drawn to represent a given chemical specie which exhibits resonance behaviour and can otherwise be represented on paper in the form of an average of two or more chemical structures separated each from the next by a double-headed arrow.
The molecular formula for compound is 
mass of compound is 0.670 g.
To calculate number of atoms first calculate number of moles in the compound as follows:
Molar mass of is 283.886 g/mol, thus,
Thus, number of mole of is 0.00236 mol.
From the molecular formula 1 mole of has 2 mol of P (phosphorus) and 5 mol of O (oxygen).
Thus, number of moles of P and O in 0.00236 mol of will be:
Similarly,
Now, in 1 mol of an element there are 
atoms.
Number of atoms of P will be:
Similarly, number of atoms of O will be:
Total number of atoms will be sum of number of atoms of P and O:
Therefore, total number of atoms in will be 
.
