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3 years ago

What are these means in Periodic Table; Group Period Block

1 answer:

5 0

1. Group: Groups shows the number of valence electrons and are shown in columns on the periodic table.

2. Period: Periods show the number of energy levels each element has and are shown in rows on the periodic table (up and down).

3. Blocks are show the amount of orbitals each element has. There is an s block, d block, p block, and f block.

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HELP PLSSSSSSS IM SO DUMMMMMMMMMMMMMMMMMMMMM AHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH

vekshin1

Answer:

I'm sorry but I'm not doing the whole test

Explanation:

5 0

3 years ago

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The three naturally occurring isotopes of potassium are 39K, 38.963707u; 40K, 39.963999u; and 41K.The percent natural abundances

sweet-ann [11.9K]

Answer:

The isotopic mass of 41K is 40.9574 amu

Explanation:

Step 1: Data given

The isotopes are:

39K with an isotopic mass of 38.963707u and natural abundance of 93.2581%

40K with an isotopic mass of 39.963999u

41K wit natural abundance of 6.7302 %

Average atomic mass =39.098 amu

Step 2: Calculate natural abundance of 40 K

100 % - 93.2581 % - 6.7302 %

100 % = 0.0117 %

Step 3: Calculate isotopic mass of 41K

39.098 = 38.963707 * 0.932581 + 39.963999 * 0.000117 + X * 0.067302

39.098 = 36.33681 + 0.0046758 + X * 2.067302

X = 40.9574 amu

The isotopic mass of 41K is 40.9574 amu

8 0

4 years ago

The concentrated sulfuric acid we use in the laboratory is 98.0% sulfuric acid by weight. Calculate the molality and molarity of

timama [110]

Answer : The molarity and molality of the solution is, 18.29 mole/L and 499.59 mole/Kg respectively.

Solution : Given,

Density of solution = $1.83g/cm^3=1.83g/ml$

Molar mass of sulfuric acid (solute) = 98.079 g/mole

98.0 % sulfuric acid by mass means that 98.0 gram of sulfuric acid is present in 100 g of solution.

Mass of sulfuric acid (solute) = 98.0 g

Mass of solution = 100 g

Mass of solvent = Mass of solution - Mass of solute = 100 - 98.0 = 2 g

First we have to calculate the volume of solution.

$\text{Volume of solution}=\frac{\text{Mass of solution}}{\text{Density of solution}}=\frac{100g}{1.83g/ml}=54.64ml$

Now we have to calculate the molarity of solution.

$Molarity=\frac{\text{Mass of solute}\times 1000}{\text{Molar mass of solute}\times \text{volume of solution}}=\frac{98.0g\times 1000}{98.079g/mole\times 54.64ml}=18.29mole/L$

Now we have to calculate the molality of the solution.

$Molality=\frac{\text{Mass of solute}\times 1000}{\text{Molar mass of solute}\times \text{Mass of solvent}}=\frac{98.0g\times 1000}{98.079g/mole\times 2g}=499.59mole/Kg$

Therefore, the molarity and molality of the solution is, 18.29 mole/L and 499.59 mole/Kg respectively.

7 0

3 years ago

Which of the following statements about subatomic particles best characterizes electrons? A positive charge, light, circling the

schepotkina [342]

Every electron carries one elementary negative charge. Concerning mass,
it takes roughly 1,840 electrons to make enough mass for 1 proton or 1 neutron.
Electrons don't necessarily have to stay connected to an atom, but when they do,
they circle the nucleus.

So you should select (C): ==> Negative, ==> light, ==> circling the nucleus.

7 0

3 years ago

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Which of the following is an example of a physical change?

o-na [289]

Answer:

I think b is the correct answer

7 0

3 years ago

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