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2 years ago

Select the correct boxes. which two elements have the same number of valence electrons?

Chemistry

1 answer:

Simora [160]2 years ago

3 0

Carbon and silicon have same number of valance electrons which is 4 electrons

Now, Barium is a 2nd group element. So, it has two valance electrons.

Silicon is a 16th group element and it has 4 valance electrons as does the carbon. This is because they both stay in the same group in the periodic table.

Neon is a noble gas which has 8 valance electrons and stays in the 18th group.

Therefore, carbon and silicon have same number of valance electrons which is 4 electrons.

<h3>What are Valence electrons ?</h3>

The electrons in an atom's outermost shell, or energy level, are called valence electrons. For instance, the valence electrons of oxygen are six, with two in the 2s subshell and four in the 2p subshell.

The number of valence electrons for neutral atoms is the same as the number of the atom's main group. A periodic table element's column can be used to determine its main group number. For instance, carbon, which belongs to group 4, has four valence electrons. Group 6 oxygen contains six valence electrons.

Learn more about Valence electrons here:

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Question 6 of 10

Levart [38]

Answer:

C. Solids made of molecules

3 0

2 years ago

Urea makes up a significant amount of urine, and is the chemical that the body uses to rid cells of unwanted carbon dioxide and

Ira Lisetskai [31]

Urea is highly soluble in water. When it is allowed to dissolve in water in the presence of heat, it will yield ammonia and carbon dioxide. The reaction is shown below:

<span>NH2-CO-NH2 + H2O </span>⇒ 2 NH3 + CO2

As you can observe in the stoichiometric equations, 1 molecule of water can dissolve with 1 mole of urea.

3 0

3 years ago

Express the following in regular notation:<br> 3.4 x 10-1

sweet-ann [11.9K]

Answer:

hen working with very large or very small numbers, scientists, mathematicians, and engineers often use scientific notation to express those quantities. Scientific notation uses exponential notation. The following are examples of scientific notation.

Light year: number of miles light travels in one year, about 5,880,000,000,000

Scientific notation is 5.88 x 1012 miles.

hydrogen atom: has a diameter of about 0.00000005 mm

Scientific notation is 5 x 10-8 mm

Computation with very large numbers is made easier with scientific notation.

Learning to Use Scientific Notation

When a number is written in scientific notation, the exponent tells you if the term is a large or a small number. A positive exponent indicates a large number and a negative exponent indicates a small number that is between 0 and 1.

Since it’s so useful, let’s look more closely at the details of scientific notation format.

Scientific Notation

A positive number is written in scientific notation if it is written as a x 10n where the coefficient a has a value such that 1 ≤ a < 10 and n is an integer.

Look at the numbers below. Which of the numbers is written in scientific notation?

Number

Scientific Notation?

Explanation

1.85 x 10-2

yes

1 ≤1.85 < 10

-2 is an integer

is not an integer

0.82 x 1014

0.82 is not ≥ 1

10 x 103

10 is not < 10

Which number below is written in scientific notation?

A) 4.25 x 100.08

B) 0.425 x 107

C) 42.5 x 105

D) 4.25 x 106

Show/Hide Answer

Writing Decimal Notation in Scientific Notation

Now let’s compare some numbers expressed in both scientific notation and standard decimal notation in order to understand how to convert from one form to the other. Take a look at the tables below. Pay close attention to the exponent in the scientific notation and the position of the decimal point in the decimal notation.

Large Numbers

Small Numbers

Decimal Notation

Scientific Notation

Decimal Notation

Scientific Notation

500.0

5 x 102

0.05

5 x 10-2

80,000.0

8 x 104

0.0008

8 x 10-4

43,000,000.0

4.3 x 107

0.00000043

4.3 x 10-7

62,500,000,000.0

6.25 x 1010

0.000000000625

6.25 x 10-10

To write a large number in scientific notation, move the decimal point to the left to obtain a number between 1 and 10. Since moving the decimal point changes the value, you have to multiply the decimal by a power of 10 so that the expression has the same value.

Let’s look at an example.

180,000. = 18,000.0 x 101

1,800.00 x 102

180.000 x 103

18.0000 x 104

1.80000 x 105

180,000 = 1.8 x 105

Notice that the decimal point was moved 5 places to the left, and the exponent is 5.

The world population is estimated to be about 6,800,000,000 people. Which answer expresses this number in scientific notation?

A) 7 x 109

B) 0.68 x 1010

C) 6.8 x 109

D) 68 x 108

Show/Hide Answer

Advanced Question

Represent 1.00357 x 10-6 in decimal form.

A) 1.00357000000

B) 0.000100357

C) 0.000001357

D) 0.00000100357

Show/Hide Answer

To write a small number (between 0 and 1) in scientific notation, you move the decimal to the right and the exponent will have to be negative.

0.00004 = 00.0004 x 10-1

000.004 x 10-2

0000.04 x 10-3

00000.4 x 10-4

000004. x 10-5

0.00004 = 4 x 10-5

0.82 x 10-6

3 0

3 years ago

Read 2 more answers

Difference between---<br> soap and detergent

guapka [62]

Answer:

"Soaps are made from natural ingredients, such as plant oils (coconut, vegetable, palm, pine) or acids derived from animal fat. Detergents, on the other hand, are synthetic, man-made derivatives. While soap is limited in its applications, detergents can be formulated to include other ingredients for all sorts of cleaning purposes. Perhaps the most common and versatile of these ingredients are surfactants … surface active agents.

The main difference between soap and detergent is the ingredients. Soaps are made with biodegradable ingredients such as oils, lye and fats. ... Both clean clothes well, but detergents are more effective on stains and with brightening clothes. However, soap is kinder on the environment and skin. "

Hope this helps

Excerpt from textbook

8 0

2 years ago

Be sure to answer all parts. For the complete redox reactions given here, write the half-reactions and identify the oxidizing an

OlgaM077 [116]

Answer : $O_2$ is the oxidizing agent and Fe is the reducing agent.

Explanation :

Reducing agent : It is defined as the agent which helps the other substance to reduce and itself gets oxidized. Thus, it will undergo oxidation reaction.

Oxidizing agent : It is defined as the agent which helps the other substance to oxidize and itself gets reduced. Thus, it will undergo reduction reaction.

The balanced redox reaction is :

$4Fe+3O_2\rightarrow 2Fe_2O_3$

The half oxidation-reduction reactions are:

Oxidation reaction : $Fe\rightarrow Fe^{3+}+3e^-$

Reduction reaction : $O_2+4e^-\rightarrow 2O^{2-}$

In order to balance the electrons, we multiply the oxidation reaction by 4 and reduction reaction by 3 then added both equation, we get the balanced redox reaction.

Oxidation reaction : $4Fe\rightarrow 4Fe^{3+}+12e^-$

Reduction reaction : $3O_2+12e^-\rightarrow 6O^{2-}$

$4Fe+3O_2\rightarrow 2Fe_2O_3$

In this reaction, $'Fe'$ is the reducing agent that loses an electron to another chemical species in a redox chemical reaction and itself gets oxidized and $'O_2'$ is the oxidizing agent that gain an electron to another chemical species in a redox chemical reaction and itself gets reduced.

Thus, $O_2$ is the oxidizing agent and Fe is the reducing agent.

7 0

3 years ago