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2 years ago

How does a scientist know where on the periodic table to put a newly discovered element?

Chemistry

1 answer:

deff fn [24]2 years ago

5 0

Explanation:

Periodic table has vertical columns and horizontals rows.

Periods: The horizontal rows are named as periods in a periodic table.In a period elements with same numbers of principle quantum number ('n') or total number of shells (energy levels) are present. For example : Sodium comes in third period which means that sodium has three shells in total.

Groups: The vertical columns are named as group in a periodic table. In a group elements with same number electrons in their outermost shell are present. For example: In group one all the elements Li, Na, K etc have same number of valence electrons in their outermost shell.

So, in order to place a newly discovered element in a periodic table scientist must have the information regarding the number of valence electrons and total number of shells present in an atom of that element. One can easily look for valence number of electrons and total number of shells from the atomic number of that particular element.

By the knowledge of valence electrons and total number of shells the scientist will able to decide the group number and period number for newly discovered element.

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Which properties of glass are a promblem in transporting food and drink?

poizon [28]

Answer:

awww this is so cuteeeee

Explanation:

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2 years ago

Read 2 more answers

Consider the hypothetical reaction 4A + 3B → C + 2D Over an interval of 3.00 s the average rate of change of the concentration o

pogonyaev

Answer:

Final concentration of C at the end of the interval of 3s if its initial concentration was 3.0 M, is 3.06 M and if the initial concentration was 3.960 M, the concentration at the end of the interval is 4.02 M

Explanation:

4A + 3B ------> C + 2D

In the 3s interval, the rate of change of the reactant A is given as -0.08 M/s

The amount of A that has reacted at the end of 3 seconds will be

0.08 × 3 = 0.24 M

Assuming the volume of reacting vessel is constant, we can use number of moles and concentration in mol/L interchangeably in the stoichiometric balance.

From the chemical reaction,

4 moles of A gives 1 mole of C

0.24 M of reacted A will form (0.24 × 1)/4 M of C

Amount of C formed at the end of the 3s interval = 0.06 M

If the initial concentration of C was 3 M, the new concentration of C would be (3 + 0.06) = 3.06 M.

If the initial concentration of C was 3.96 M, the new concentration of C would be (3.96 + 0.06) = 4.02 M

3 0

2 years ago

What mass of NH3 can be made from 35.0g of N2?

egoroff_w [7]

Formation of ammonia by nitrogen and hydrogen is habers process wher 28g N2 results in formation of 34g NH3
so 35g N2 will form 34*35/28=42.5g NH3 where it given that reaction takes place in excess of H2
N2+3H2 gives 2NH3

4 0

2 years ago

Read 2 more answers

One kilogram of water at 100 0C is cooled reversibly to 15 0C. Compute the change in entropy. Specific heat of water is 4190 J/K

mina [271]

Answer:

The change in entropy is -1083.112 joules per kilogram-Kelvin.

Explanation:

If the water is cooled reversibly with no phase changes, then there is no entropy generation during the entire process. By the Second Law of Thermodynamics, we represent the change of entropy ( $s_{2} - s_{1}$ ), in joules per gram-Kelvin, by the following model:

$s_{2} - s_{1} = \int\limits^{T_{2}}_{T_{1}} {\frac{dQ}{T} }$

$s_{2} - s_{1} = m\cdot c_{w} \cdot \int\limits^{T_{2}}_{T_{1}} {\frac{dT}{T} }$

$s_{2} - s_{1} = m\cdot c_{w} \cdot \ln \frac{T_{2}}{T_{1}}$ (1)

Where:

$m$ - Mass, in kilograms.

$c_{w}$ - Specific heat of water, in joules per kilogram-Kelvin.

$T_{1}$ , $T_{2}$ - Initial and final temperatures of water, in Kelvin.

If we know that $m = 1\,kg$ , $c_{w} = 4190\,\frac{J}{kg\cdot K}$ , $T_{1} = 373.15\,K$ and $T_{2} = 288.15\,K$ , then the change in entropy for the entire process is:

$s_{2} - s_{1} = (1\,kg) \cdot \left(4190\,\frac{J}{kg\cdot K} \right)\cdot \ln \frac{288.15\,K}{373.15\,K}$

$s_{2} - s_{1} = -1083.112\,\frac{J}{kg\cdot K}$

The change in entropy is -1083.112 joules per kilogram-Kelvin.

7 0

2 years ago

A topographical map of a section of Charleston, SC is shown. What feature is located at the dot marked with an X? A) the center

Effectus [21]

It seems that you have missed the given image to answer this question. But anyway, I found it and got the answer. Based on the topographical map of a section of Charleston, SC, the feature that is <span>located at the dot marked with an X is the high point of a hill. The answer would be option D.</span>

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2 years ago