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3 years ago

How many neutrons and protons are there in the nuclei of the following atoms. a. Li-7 b. O-16 c. Th-232 d. Pu-239

Chemistry

1 answer:

ANEK [815]3 years ago

3 0

Answer:

P = 3 , N = 4

P = 8 , N = 8

P = 90 , N = 142

P = 94 , N = 145

Explanation:

Mass number = Number of protons + Number of neutrons

Also,

Atomic number = Number of protons

Given, Mass number of Lithium = 7

For lithium, atomic number = 3

So,

Number of protons = 3

Number of neutrons = Mass number - Number of protons = 7 - 3 = 4

Given, Mass number of oxygen = 16

For oxygen, atomic number = 8

So,

Number of protons = 8

Number of neutrons = Mass number - Number of protons = 16 - 8 = 8

Given, Mass number of Thorium = 232

For Thorium, atomic number = 90

So,

Number of protons = 90

Number of neutrons = Mass number - Number of protons = 232 - 90 = 142

Given, Mass number of Plutonium = 239

For Plutonium, atomic number = 94

So,

Number of protons = 94

Number of neutrons = Mass number - Number of protons = 239 - 94 = 145

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D) anomalous volcanoes such as those in Hawaii

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2 years ago

X, Y & Z represents 2, 12 & 17 relatively a. Write the electronic configuration of x, y, and z b. Place the elements in

olasank [31]

The electronic configuration of x, y, and z.

$x=1s^2$

$Y= 1s^22s^22p^63s^2$

$Z= 1s^22s^22p^63s^23p^5$

<h3>What is an electronic configuration?</h3>

Electronic configuration, also called electronic structure, is the arrangement of electrons in energy levels around an atomic nucleus.

$x=1s^2$

$Y= 1s^22s^22p^63s^2$

$Z= 1s^22s^22p^63s^23p^5$

x= Period 1 and group18

Y=Element is in period 3 and Group 2

Z=Element is in period 3 and group 17.

X, Y & Z represents Helium, magnesium, and chlorine.

Learn more about the electronic configuration here:

brainly.com/question/19589767

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3 0

2 years ago

A sample of basalt has smaller crystals than a sample of granite. What is the most likely reason for this?

posledela

The most likely reason is that basalt is an extrusive rock, while granite is an intrusive rock. What this means is that basalt forms at the surface of the earth, where temperatures are cooler. Because of the cooler external temperature, basalt cools relatively quickly, and there isn't as much time for mineral crystals within the rock to align to form larger crystals while the rock is cooling. Granite, on the other hand, forms below the surface of the earth, where temperatures are significantly higher. Therefore, it doesn't cool as quickly, and the minerals within granite have more time to form larger crystals and the rock cools.

4 0

2 years ago

PLEASE HELP FOR THIS ASSIGNMENT

mars1129 [50]

<h2>Steps:</h2>

Remember that Density = mass/volume, or D = m/v

So firstly, we have to find the volume of the rock. To do this, we need to subtract the volume of water A from the volume of the water B. In this case:

Water A = 30 mL
Water B = 40 mL
40 mL - 30 mL = 10 mL

<u>The volume of the rock is 10 mL.</u>

Now that we have the volume, we can plug that and the density of the rock into the density equation to solve for the mass.

$3.678=\frac{m}{10}$

For this, multiply both sides by 10:

$36.78=m$

<h2>Answer:</h2>

<u>Rounding to the tenths place, the mass of the rock is 36.8 g, or C.</u>

6 0

3 years ago

How many moles of argon, Ar, are in 1.31×1024 Ar atoms?

ddd [48]

Answer:

2.18 mol Ar.

Explanation:

Hello there!

In this case, according to the definition of mole as the amount of particles of a given substance, it is possible to introduce the Avogadro's number to assert that 1 mole of any element contains 6.022x10²³ atoms; thus, the moles of Ar in the given amount of atoms turns out to be:

$1.31x10^{24}Ar atoms*\frac{1molAr}{6.022x10^{23}atoms}\\\\=2.18molAr$

Best regards!

5 0

2 years ago