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riadik2000 [5.3K]
3 years ago
5

Imagine you are given a mystery element. It is, however, a discovered and known element. You may perform a maximum of two observ

ations or tests to determine its identity. Time and money is critical, so you need to prioritize your tests. If you can identify the mystery element with a single test, you get 100 super-geek points from your research lab team.
Pick two tests and justify why you think they will identify the mystery element with certainty. If you think the first test will be enough, explain why.

Choose from these available tests:
• classification into metal, nonmetal, or metalloid
• count of valence electrons
• count of electron shells
• atomic radius (error range: +/- 1 pm)
• electronegativity (error range: +/- 0.1)
• first ionization energy (error range: +/- 10 kJ/mole)
• melting point (error range: +/- 10 C)
• boiling point (error range: +/- 20 C)

Chemistry
2 answers:
miv72 [106K]3 years ago
6 0

The classification of it being a metal, nonmetal, or metalliod will be useful in the process of elimination to determine what it is. Then for the second test, meauring the atomin radius will narrow it down quicker to the mystery elemet's name.

Since you determined what part of the periodic table it's on, then when measuring the atomic radius, you should be able to pinpoint what the element is more surely.

Nadusha1986 [10]3 years ago
3 0

Answer:

Count of Valence electron followed by electron shells

Explanation:

The periodic table has certain very unique properties that help identify the elements.

The number of valence electrons in any element can be determined by the placement of the element in the group. An element from group III will have three valence electrons.

Hence, this test will help locate the group of the element in question.

This test should be followed by the number of electron shells.

In the Periodic table, the placement of any element in the row depends on the number of electron shells. An element from row II will have two electron shell.

These two tests will work like coordinates on the Periodic Table.

For example, the result is Group II, Row 3 is Calcium.

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mrs_skeptik [129]
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8 0
3 years ago
Ap chemistry how to determine if compound is ionic or molecular bqsed on formula
ludmilkaskok [199]
Ionic compound consists of a positively charged ion and a negatively charged anion. For example, NaCl. Na (sodium) is a cation (another word for positively charged ion) and Cl (chloride) is a anion (another way for negatively charged ion.)

Molecular compounds consists of only negatively charged ions. For example Br2I is a compound of 2 elements that are negatively charged.

Unlike ionic compounds, molecular compounds consists of two or more negatively charged elements.  
7 0
3 years ago
The rate constant for the decomposition of nitrogen dioxide NO2(g) LaTeX: \longrightarrow⟶ NO (g) + 1/2 O2(g) with a laser beam
aleksley [76]

Answer :

The time taken by the reaction is 19.2 seconds.

The order of reaction is, second order reaction.

Explanation :

The general formula to determine the unit of rate constant is:

(Concentration)^{(1-n)}(Time)^{-1}

Unit of rate constant                           Order of reaction

Concentration/Time                                        0

Time^{-1}                                                              1

(Concentration)^{-1}Time^{-1}                                 2

As the unit of rate constant is M^{-1}min^{-1}. So, the order of reaction is second order.

The expression used for second order kinetics is:

kt=\frac{1}{[A_t]}-\frac{1}{[A_o]}

where,

k = rate constant = 1.95M^{-1}s^{-1}

t = time = ?

[A_t] = final concentration = 0.97 M

[A_o] = initial concentration = 2.48 M

Now put all the given values in the above expression, we get:

1.95\times t=\frac{1}{0.97}-\frac{1}{2.48}

t=0.32min=0.32\times 60s=19.2s

Therefore, the time taken by the reaction is 19.2 seconds.

8 0
3 years ago
In the laboratory you are asked to make a 0.565 m sodium bromide solution using 315 grams of water. How many grams of sodium bro
Scorpion4ik [409]

Answer : The mass of sodium bromide added should be, 18.3 grams.

Explanation :

Molality : It is defined as the number of moles of solute present in kilograms of solvent.

Formula used :

Molality=\frac{\text{Mass of solute}\times 1000}{\text{Molar mass of solute}\times \text{Mass of solvent}}

Solute is, NaBr and solvent is, water.

Given:

Molality of NaBr = 0.565 mol/kg

Molar mass of NaBr = 103 g/mole

Mass of water = 315 g

Now put all the given values in the above formula, we get:

0.565mol/kg=\frac{\text{Mass of NaBr}\times 1000}{103g/mole\times 315g}

\text{Mass of NaBr}=18.3g

Thus, the mass of sodium bromide added should be, 18.3 grams.

6 0
3 years ago
In CF4 and NF3, the ___electron groups on the central C and N atoms have a ___ arrangement. The shapes of the molecules are dete
enyata [817]

Answer:

Explanation:

In CF4 and NF3, the valence electron groups on the central C and N atoms have a tetrahedral arrangement. The shapes of the molecules are determined by the number of bonding and nonbonding of electrons: since CF4 has four bonded atom(s) and zero lone pair(s) of electrons, the shape is tetrahedral.

7 0
4 years ago
Read 2 more answers
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