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solniwko [45]
3 years ago
12

The electron configuration of an element is 1s2 2s2. How many valence electrons does the element have?

Chemistry
1 answer:
faust18 [17]3 years ago
7 0

Answer:

Two valence electrons

Explanation:

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The work function is the energy that must be supplied to cause the release of an electron from a photoelectric material. The cor
vladimir2022 [97]

Answer:

No photoelectric effect is observed for Mercury.

Explanation:

From E= hf

h= Plank's constant

f= frequency of incident light

Threshold Frequency of mercury= 435×10^3/ 6.6×10^-34 × 6.02×10^23

f= 11×10^14 Hz

The highest frequency of visible light is 7.5×10^14. This is clearly less than the threshold frequency of mercury hence no electron is emitted from the mercury surface

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4 years ago
Calculate the percentage by mass of the indicated element in the following compounds. Hydrogen in ascorbic acid, HC6H7O6, also k
Scorpion4ik [409]

Answer: The mass percent of hydrogen in ascorbic acid is 4.5 %

Explanation:

In C_6H_8O_6, there are 6 carbon atoms, 8 hydrogen atoms and 6 oxygen atoms.

To calculate the mass percent of element in a given compound, we use the formula:

\text{Mass percent of hydrogen}=\frac{\text{Mass of hydrogen}}{\text{Molar mass of ascorbic acid}}\times 100

Mass of hydrogen = 8\times 1g/mol=8g

Molar Mass of ascorbic acid =6\times 12g/mol+8\times 1g/mol+6\times 16g/mol=176g

Putting values in above equation, we get:

\text{Mass percent of hydrogen}=\frac{8g}{176}\times 100=4.5\%

Hence, the mass percent of of hydrogen in ascorbic acid is 4.5 %.

8 0
3 years ago
The quantity, 1,385 mg is equivalent to in scientific notation
Agata [3.3K]

Answer:

The answer is 1385 x10∧ -3

Explanation:

Scientific notation is a quick way to represent a number using notation in exponential form or powers of base ten.

This notation allows us to express too large or small numbers easily.

<u>For example: </u>

500 is written as 5x10∧2; Where the power 2 represents the number of 0's that follow 5.

0.0093 is written as 9.3x10∧-3; Where the power -3 represents the number of times the comma was moved to the right.

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3 years ago
ANYONE PLEASE HELP ME WITH MY CHEMISTRY HOMEWORK I REALLY NEED THE ANSWER RIGHT NOW I HOPE Y’ALL CAN HELP ME:(
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Answer:

what grade is this ?

Explanation:

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3 years ago
Identify the for of energy<br><br> (A)thermal<br> (B)kinetic<br> (C)chemical<br> (D)electrical
RoseWind [281]

Answer:

<u>C Chemical Energy</u>

Explanation:

food gives us chemical energy which may be transformed to other later..

<em><u>please mark me brainliest</u></em>

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3 years ago
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