Answer:
One: <u>Selenium</u> is Paramagnetic
Explanation:
Those compounds which have unpaired electrons are attracted towards magnet. This property is called as paramagnetism. Lets see why remaining are not paramagnetic.
Electronic configuration of Scandium;
Sc = 21 = 1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d¹
Sc³⁺ = 1s², 2s², 2p⁶, 3s², 3p⁶
Hence in Sc³⁺ there is no unpaired electron.
Electronic configuration of Bromine;
Br = 35 = 1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d¹⁰, 4p⁵
Br⁻ = 1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d¹⁰, 4p⁶
Hence in Br⁻ there is no unpaired electron.
Electronic configuration of Magnesium;
Mg = 12 = 1s², 2s², 2p⁶, 3s²
Mg²⁺ = 1s², 2s², 2p⁶
Hence in Mg²⁺ there is no unpaired electron.
Electronic configuration of selenium;
Se = 34 = 1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d¹⁰, 4p⁴
Or,
Se = 34 = 1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d¹⁰, 4px², 4py¹, 4pz¹
Hence in Se there are two unpaired electrons hence it is paramagnetic in nature.
Answer: 5.747 * 10^14 Hz
Explanation:
Convert 522nm to m = 522 * 10^-9 m (since 1nm=10^-9m)
If c = wavelength * frequency, where c is the speed of light (3.0 * 10^8 m/s), then you can manipulate the equation to solve for frequency (f).
f = c / wavelength
Plug in the given numbers:
f = (3.0 * 10^8) / (10^-9)
f = 5.747 * 10^14 Hz
Answer:
0.8 mL of protein solution, 9.2 mL of water
Explanation:
The dilution equation can be used to relate the concentration C₁ and volume V₁ of the stock/undiluted solution to the concentration C₂ and volume V₂ of the diluted solution:
C₁V₁ = C₂V₂
We would like to calculate the value for V₁, the volume of the inital solution that we need to dilute to make the required solution.
V₁ = (C₂V₂) / C₁ = (2mg/mL x 10mL) / (25 mg/mL) = 0.8 mL
Thus, a volume of 0.8 mL of protein solution should be diluted with enough water to bring the total volume to 10 mL. The amount of water needed is:
(10 mL - 0.8 mL) = 9.2 mL
Answer:
The difference in the number of protons and neutrons in atoms account for many of the different properties of elements.
1. Rapid combustion - <span>used in engines and rockets souring. Large amount of energy produced.
</span>2. R<span>espiration - </span><span>a type of slow combustion. Organic matter is transfered into energy and carbon dioxide.
3. Soaring - a chemical change. A</span>cidification of milk into soured milk.<span>
4. Oxidation - electron loss when combining with another element. Metals gave electrons to nonmetals and became cations.
5. C</span>alcium - element in bone which absorbs X-rays. Calcium increases the photoelectric effect<span> which increase absorption of X-rays.
6. P</span>hotosynthesis reaction in which the product is glucose. Plants produce glucose from carbon dioxide and water.
