Types of Bonds can be predicted by calculating the
difference in electronegativity.
If, Electronegativity difference is,
Less
than 0.4 then it is Non Polar Covalent
Between 0.4 and 1.7 then it is Polar Covalent
Greater than 1.7 then it is Ionic
For Be and F,
E.N of Fluorine = 3.98
E.N of Beryllium = 1.57
________
E.N Difference 2.41 (Ionic Bond)
For H and Cl,
E.N of Chorine = 3.16
E.N of Hydrogen = 2.20
________
E.N Difference 0.96 (Polar Covalent Bond)
For Na and O,
E.N of Oxygen = 3.44
E.N of Sodium = 0.93
________
E.N Difference 2.51 (Ionic Bond)
For F and F,
E.N of Fluorine = 3.98
E.N of Fluorine = 3.98
________
E.N Difference 0.00 (Non-Polar Covalent Bond)
Result:
A polar covalent bond is formed between Hydrogen and Chlorine atoms.
Answer: Option (c) is the correct answer.
Explanation:
Plants used to prepare food in the presence of sunlight. Therefore, plants uses solar energy to make food.
Due to solar energy various chemical reactions take place in the food.
Thus, we can conclude that chemical energy is stored in our food and this chemical energy start out as light energy from the sun.
Answer:
- <u>Cadmium has larger atomic radius than sulfur.</u>
Explanation:
Down a period, atomic radii decrease from left to right due to the increase in the number of protons and electrons across a period: when a proton is added the pull of the electrons towards the nucleus is larger, so the size of the atom decreases.
Hence, you can compare the elements that belong to a same period and predict that the atom with lower atomic number (number of protons) will haver larger atomic radius. With that:
- Oxygen and fluorine are in the period 3, being oxygen to the left of fluorine, so oxygen is larger than fluorine.
- Sulfur and chlorine are in the period 4, being sulfur to the left of chlorine, so sulfur is larger than chlorine.
Now see whan happens down a group. Atomic radius increases from top to bottom within a group due to electron shielding. That permits you to compare the size of the elements in a group:
- Fluorine and chlorine are in the same group (17), with chlorine directly below fluorine, so the atomic radius of chlorine is larger than the atomic radius of fluorine.
- Sulfur and oxygen are in the same group (16), with sulfur directlly below oxygen, so sulfur the atomic radius of sulfur is larger than the atocmi radius of oxygen.
So far, you can rank the atomic radius of sulfur, chlorine, fluorine, and oxygen, in increasing order as:
- O < F < Cl < S, concluding that O, F, and Cl have smaller atomic radius than S.
Cadmiun, Cd, is to the left and below sulfur, so both electron shielding (down a group) and increase of the number of protons (down a period) lead to predict the cadmium has a larger atomic radius than sulfur.
Answer : The rms speed of the molecules in a sample of 
gas at 300 K will be four times larger than the rms speed of 
molecules at the same temperature, and the ratio 
constant with increasing temperature.
Explanation :
Formula used for root mean square speed :
where,
= rms speed of the molecule
R = gas constant
T = temperature
M = molar mass of the gas
At constant temperature, the formula becomes,
And the formula for two gases will be,
Molar mass of = 32 g/mole
Molar mass of = 2 g/mole
Now put all the given values in the above formula, we get
Therefore, the rms speed of the molecules in a sample of gas at 300 K will be four times larger than the rms speed of molecules at the same temperature.
And the ratio constant with increasing temperature because rms speed depends only on the molar mass of the gases at same temperature.
The number of electrons when the quantum number n=2 is 8 electrons. Variab<span>le </span>n<span> represents the principal quantum number which is the number of the energy level. </span>
