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Contact [7]
4 years ago
5

How many shells are occupied in atoms of elements in period 4?

Chemistry
1 answer:
choli [55]4 years ago
8 0

Explanation:

Since, Number of shells in an atom = number of period

Therefore, atoms of element will have 4 shells.

For example:

K (Potassium) is an element of 4th period whose atomic number is 19.

19 = 2, 8, 8, 1

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How did Ernest Rutherford’s experiment relate to J.J. Thomson’s work?
horsena [70]
Thomson realized that the accepted model of an atom did not account for negatively or positively charged particles. Therefore, he proposed a model of the atom which he likened to plum pudding. ... Rutherford with the assistance of Ernest Marsden and Hans Geiger performed a series of experiments using alpha particles.
8 0
3 years ago
An empty beaker weighs 39.09 g
Vinvika [58]
<span>To work out the volume of something from its density, use the compound measures triangle: mass over density and volume. To find volume that the beaker holds, divide the mass by the density. V = (388.15 - 39.09)/1. V = 349.06g/cm3. To find the weight of the beaker and the contents, first work out the weight (mass) of the mercury, with this formula: mass = d x v. M = 13.5 x 349.06. M = 4712.31. Then add on the weight of the beaker (39.09g). The total weight is 4751.40g.</span>
3 0
3 years ago
Who first established the heliocentric view
Alexus [3.1K]
This theory was created by Nicoulas Copernicus
4 0
3 years ago
A 14.1% by mass HClO3 solution has a density of 1.1690 g/mL. What is the concentration of this solution in molarity?
Scilla [17]

Answer:

[ HClO₃] = 1.93M

Explanation:

X % by mass, means that in 100 g of solution, we have X g of solute.

In this case, 14.1 g of HClO₃ are contained in 100 g of solution.

Density always referrs to solution. Let's calculate the volume of solution.

Solution density = Solution mass / Solution volume

1.1690 g/mL = 100 g / Solution volume

Solution volume = 100 g /1.1690 g/mL → 86.2 mL.

For molarity we must get moles of solute and volume of solution (L), because molarity is mol/L

Let's convert the mL of solution in L

86.2 mL . 1L / 1000mL = 0.0862 L

Now, let's determine the moles of solute. (Mass / Molar mass)

14.1 g / 84.45 g/mol = 0.167 moles

Molarity is mol/L →  0.167 moles / 0.0862 L = 1.93M

6 0
4 years ago
A certain drug has a half-life in the body of 3.5h. Suppose a patient takes one 200.Mg pill at :500PM and another identical pill
tekilochka [14]

Answer:

The amount of drug left in his body at 7:00 pm is 315.7 mg.

Explanation:

First, we need to find the amount of drug in the body at 90 min by using the exponential decay equation:

N_{t} = N_{0}e^{-\lambda t}

Where:

λ: is the decay constant = ln(2)/t_{1/2}

t_{1/2}: is the half-life of the drug = 3.5 h

N(t): is the quantity of the drug at time t

N₀: is the initial quantity

After 90 min and before he takes the other 200 mg pill, we have:

N_{t} = 200e^{-\frac{ln(2)}{3.5 h}*90 min*\frac{1 h}{60 min}} = 148.6 mg

Now, at 7:00 pm we have:

t = 7:00 pm - (5:00 pm + 90 min) = 30 min

N_{t} = (200 + 148.6)e^{-\frac{ln(2)}{3.5 h}*30 min*\frac{1 h}{60 min}} = 315.7 mg    

Therefore, the amount of drug left in his body at 7:00 pm is 315.7 mg (from an initial amount of 400 mg).

I hope it helps you!

3 0
3 years ago
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