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1 year ago

Which of the elements are nonmetals?

Chemistry

2 answers:

Elis [28]1 year ago

8 0

The answer is E and F.

Hope this helps!!

MakcuM [25]1 year ago

3 0

Answer:

carbon, Iodine, Selenium, and Boron

Explanation:

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Why are scientists concerned with finding Earth-like planets?

sdas [7]

Over the last few days, NASA has been getting everybody excited with its plans to hold a high profile briefing about a discovery beyond our solar system. Now we know that the announcement concerns the discovery of seven planets orbiting a star elsewhere in our galaxy. hope this helps

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2 years ago

Read 2 more answers

Classify each of these compounds as a Brønsted-Lowry acid, a Brønsted-Lowry base, or neither.

chubhunter [2.5K]

Answer:

Brønsted-Lowry acid : H2SO4, HF, HNO2

Brønsted-Lowry Base : NH3, C3H7NH2, CH3)3N

Neither : NaBr, CCl4

Explanation:

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3 years ago

Group 8A of the periodic table contains the A. most reactive nonmetals. B. least reactive nonmetals. C. most reactive metals. D.

aivan3 [116]

Answer: The correct answer is option B.

Explanation: There are 7 elements in group VIII-A. They are Helium (He), Neon(Ne), Argon(Ar), Krypton (Kr), Xenon (Xe), Radon (Rn) and Ununoctium (Uuo). They are considered as a part of group 18.

Metals are shown in purple color in the periodic table. Metalloids as blue color and Non-metals are shown in green color.

Group VIII-A elements have fully filled orbitals and hence are most stable amongst all the elements in the periodic table. They are considered as least reactive elements and as they are categorized as non-metals. So, they are the least reactive non-metals.

Therefore, the correct option is B.

7 0

2 years ago

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Calculate the radius ratio for NaBr if the ionic radii of Na + and Br − are 102 pm and 196 pm , respectively. radius ratio: Base

Fudgin [204]

Answer : The expected coordination number of NaBr is, 6.

Explanation :

Cation-anion radius ratio : It is defined as the ratio of the ionic radius of the cation to the ionic radius of the anion in a cation-anion compound.

This is represented by,

$\frac{r_{cation}}{r_{anion}}$

When the radius ratio is greater than 0.155, then the compound will be stable.

Now we have to determine the radius ration for NaBr.

Given:

Radius of cation, $Na^+$ = 102 pm

Radius of cation, $Br^-$ = 196 pm

$\frac{r_{cation}}{r_{anion}}=\frac{102}{196}=0.520$

As per question, the radius of cation-anion ratio is between 0.414-0.732. So, the coordination number of NaBr will be, 6.

The relation between radius ratio and coordination number are shown below.

Therefore, the expected coordination number of NaBr is, 6.

8 0

2 years ago

A sample taken from a layer of mica in a canyon has 2.10 grams of potassium-40. A test reveals it to be 2.6 billion years old. H

Setler79 [48]

Problem One

Formula

N(t) = No * (1/2)^[t/t_1/2]

Givens

N(t) = the current mass of the sample = 2.10 grams

No = The original mass of the sample = No [We're trying to find this].

t = time elapsed which is 2.6 billion years or 2.6 * 10^9 years.

t1/2 = the 1/2 life time which is 1.3 billion years of 1.3 *10^9

Solution

2.10 grams = No (1/2)^(2.6*10^9/1.3 * 10^9)

The 10^9s cancel and you are left with 2.6/1.3 = 2

2.10 grams = No (1/2)^2

2.10 grams = No (1/4) Multiply both sides by 4

2.10 * 4 = No (1/4)*4

8.4 grams = No

which is how many grams you originally had.

Answer B.

Problem Two

$_{1}^{2}\text{H} + _{1}^{2}\text{H} \longrightarrow _{z}^{y}\text{x}+_{0}^{1}\text{n}$

Solve for y

2 + 2 = y + 1

4 = y + 1

y = 3

Solve for z

1 + 1 = z + 0

z = 2

The 2 tells you that it is the second member on the periodic table. That's Helium. So the answer looks like this.

$_{2}^{3}\text{He}$

The mass of the Helium is 3 and its number is two.

5 0

2 years ago