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2 years ago

Which of the following elements contains 7 valence electrons?

Chemistry

2 answers:

Evgesh-ka [11]2 years ago

7 0

Answer:

Halogens

Explanation:

Because elements can have 8 valence elctrons so noble gas group 18 has 8 valence electrons and previous group before group 18 or noble gas is called Halogens or group 17 whatever you want to prefer periodic table has all of informations

Liono4ka [1.6K]2 years ago

6 0

Answer:

Elements: F, Cl, Br, I, At

Explanation:

Hi there,

When you are trying to find the valence electrons for an element, look at the last number of the electron configuration.

For example, if you want to find the number of valence electrons of Carbon (C), you notice that the electron configuration is<u> 2 - 4.</u>

We know that this element has four valence electrons because the last number in its electron configuration is 4.

For your question, simply find all of the elements that have the number 7 as the last number on its electron configuration on the periodic table.

Hope this answer was helpful. Cheers.

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A large piece of jewelry has a mass of 132.6 g. a graduated cylinder initially contains 48.6 ml water. when the jewelry is subme

Simora [160]

Answer:- Density is 10.5 grams per mL and the substance is Silver(Ag).

Solution:- Mass of jewelry is given as 132.6 g. Initial volume of water in the graduated cylinder is 48.6 mL and the volume becomes 61.2 mL when this jewelry is submerged in the cylinder.

So, the volume of the jewelry = 61.2 mL - 48.6mL = 12.6 mL

We know that, $density=\frac{mass}{volume}$

Let's plug in the values in the above formula to calculate the density:

$density=\frac{132.6g}{12.6mL}$

$density=10.5\frac{g}{mL}$

So, the density of the jewelry is $10.5\frac{g}{mL}$ .

The substance from which the jewelry is made could easily be identified by comparing the calculated density with the density values given for different substances in the density table.

Looking at the density table, 10.5 grams per mL is the density for silver. So, the jewelry is made up from Silver.

4 0

3 years ago

The normal freezing point of water is 0.00 ⁰C. What is the freezing point of a solution containing450.0 mg of ethylene glycol (M

anyanavicka [17]

Answer:

Freezing T° of solution = - 8.98°C

Explanation:

We apply Freezing point depression to solve this problem, the colligative property that has this formula:

Freezing T° of pure solvent - Freezing T° of solution = Kf . m

Kf = 1.86°C/m, this is a constant which is unique for each solvent. In this case, we are using water

m = molality (moles of solute / 1kg of solvent)

We convert the mass of solvent from g to kg

1.5 g . 1kg/1000g = 0.0015 kg

We convert the mass of solute, to moles. Firstly we make this conversion, from mg to g → 450mg . 1g/1000mg = 0.450 g

0.450 g. 1mol / 62.07g = 7.25×10⁻³ moles

Molality → 7.25×10⁻³ mol / 0.0015 kg = 4.83 m

- Freezing T° of solution = 1.86°C /m . 4.83 m - Freezing T° of pure solvent

-Freezing T° of solution = 1.86°C /m . 4.83 m - 0°C

Freezing T° of solution = - 8.98°C

8 0

2 years ago

Read 2 more answers

A compound has a molar mass of 100 g/mol and the percent composition (by mass) of 65.45% C, 5.45% H, and 29.09% 0. Determine the

coldgirl [10]

Answer:

B) C3H3O and C6H6O2

Explanation:

Given data:

Molar mass of compound = 100 g/mol

Percentage of hydrogen = 5.45%

Percentage of carbon = 65.45%

Percentage of oxygen = 29.09%

Empirical formula = ?

Molecular formula = ?

Solution:

Number of gram atoms of H = 5.45 / 1.01 = 5.4

Number of gram atoms of O = 29.09/ 16 = 1.8

Number of gram atoms of C = 65.45 / 12 = 5.5

Atomic ratio:

C : H : O

5.5/1.8 : 5.4/1.8 : 1.8/1.8

3 : 3 : 1

C : H : O = 3 : 3 : 1

Empirical formula is C₃H₃O.

Molecular formula:

Molecular formula = n (empirical formula)

n = molar mass of compound / empirical formula mass

Empirical formula mass = 12×3 + 1.01 ×3 + 16×1 = 55.03

n = 100 / 5503

n = 2

Molecular formula = n (empirical formula)

Molecular formula = 2 (C₃H₃O)

Molecular formula = C₆H₆O₂

3 0

2 years ago

How many pints are in a 48 cups?

Feliz [49]

1 cup = 2 pints

48 × 2 = 96 pints

HOPE THIS HELPED
:)

8 0

2 years ago

Number of atoms in compound<br><br> Mg(OH)2

Crank

ANSWER

there are 20 number of atoms in compound

Explanation:

In a formula unit of Mg(OH)2, there are one magnesium ion and two hydroxide ions; or one magnesium, two oxygen, and two hydrogen atoms.

3 0

2 years ago