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4 years ago

How are the physical and chemical properties of atoms represented on the periodic table of elements

1 answer:

8 0

Chemical properties of each elemt are determined by the elemts electroic configuration, and particulary by its outermost valence electrons. In addition, the total number of electron shells an atom determines which period it belongs to

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Using the periodic table to locate each element, write the electron configuration of(c) Re.

Aleksandr [31]

Rhenium is a chemical element with the symbol Re and atomic number 75. The electron configuration of Re is [Xe] $6s^{2} 4f^{14} 5d^{5}$ .

<h3>How to write an electronic configuration?</h3>

1. Identify the given element and its atomic number from the periodic table.

2. Write the electron configuration by the energy level and the type of orbital first, then the number of electrons present in the orbital as superscript.

The easiest way to write the electronic configuration for any element is by using a diagonal rule for electron filling order in the different subshells according to the Aufbau principle.

The 3 rules for writing the electron configuration in the orbital box diagram are – the Aufbau rule, the Pauli-exclusion rule, and Hund's Rule.

To learn more about electronic configuration, refer

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5 0

2 years ago

Now that you have exercised, walked your

ASHA 777 [7]

Answer: The moles of melatonin are 0.000043

Explanation:

According to avogadro's law, 1 mole of every substance weighs equal to its molecular mass and contains avogadro's number $6.023\times 10^{23}$ of particles.

To calculate the moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text {Molar mass}}$

Given mass of melatonin = 0.01 g

Molar mass of melatonin $(C_{13}H_{16}N_2O_2)$ = 232.28 g/mol

$\text{Number of moles of melatonin}=\frac{0.01 g}{232.28g/mol}=0.000043mol$

Thus the moles of melatonin in 0.01 g are 0.000043

4 0

3 years ago

A chemist reacted 17.25 grams of sodium metal with an excess amount of chlorine gas. The chemical reaction that occurred is show

Afina-wow [57]

<u>Answer:</u> The actual yield of the product is 38.57 g

<u>Explanation:</u>

The number of moles is defined as the ratio of the mass of a substance to its molar mass. The equation used is:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ ......(1)

We are given:

Given mass of Na = 17.25 g

Molar mass of Na = 23 g/mol

Putting values in equation 1, we get:

$\text{Moles of Na}=\frac{17.25g}{23g/mol}=0.75mol$

For the given chemical reaction:

$2Na+Cl_2\rightarrow 2NaCl$

By stoichiometry of the reaction:

2 moles of Na produces 2 moles of NaCl

So, 0.75 moles of Na will produce = $\frac{2}{2}\times 0.75=0.75mol$ of NaCl

We know, molar mass of $NaCl$ = 58.44 g/mol

Putting values in above equation, we get:

$\text{Mass of NaCl}=(0.75mol\times 58.44g/mol)=43.83g$

The percent yield of a reaction is calculated by using an equation:

$\% \text{yield}=\frac{\text{Actual value}}{\text{Theoretical value}}\times 100$ ......(1)

Given values:

Percent yield of the product = 88 %

Theoretical value of the product = 43.83 g

Plugging values in equation 1:

$88\% =\frac{\text{Actual yield}}{43.83g}\times 100\\\\\text{Actual yield}=\frac{88\times 43.83}{100}=38.57g$

Hence, the actual yield of the product is 38.57 g

3 0

3 years ago

30 point. What is formed when a hydroxyl group is substituted for a hydrogen?

Andru [333]

Haloalkanes

Yeah it’s that

6 0

3 years ago

Can someone plz help me on this. I need it really bad

kifflom [539]

Answer:

- 40.66

- 9.91

Explanation:

For the first question:

Our theoretical compound is MR₂

1 mol of MR₂ contains 1 mol of M and 2 moles of R

Let's find out the molar mass:

9.45 g/mol + 18.12 g/mol . 2 = 45.69 g/mol

We can solve this, by an easy rule of three:

1 mol of MR₂ weighs 45.69 grams

Then, 0.89 moles may weigh 40.66 g

For the second question:

Our theoretical compound is D₂G

Let's determine the molar mass:

11.45 g/mol . 2 + 44.57 g/mol = 67.47 g/mol

1 mol of anything contains 6.02×10²³ molecules. By this definition we can say that 6.02×10²³ molecules weigh 67.47 grams. Let's solve by the rule of three:

6.02×10²³ molecules weigh 67.47 g

8.84×10²² molecules may weigh (8.84×10²² . 67.47 ) / 6.02×10²³ = 9.91 g

8 0

3 years ago