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3 years ago

How was the Periodic Table of Elements developed and how are the elements arranged on it?

Chemistry

1 answer:

saw5 [17]3 years ago

5 0

Answer:

Following are the solution to this question:

Explanation:

Mendeleev has been the chemist that designed a periodic table for component identification based on the increasing number of elements. Thus, the is traditionally called a table parent and this periodic table had some drawbacks.

Consequently, Mosley rebuilt Mendeleev's periodic table to once again overcome this disadvantage. Which atoms were arranged as per the increasing order of atomic number instead of mass number. The traditional table, therefore, comprises seven horizontal lines regarded as cycles. But 18 control limits were named group lines.

The whole Periodical Tables is classified as a,p,d, and f block

S block, groups have 1 and 2.

P block, group has 13-18

D block, group has 3 to 12

F block, – Two lines far below the periodic table.

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Use the periodic table to identify the element with the electron configuration 1s²2s²2p⁴. Write its orbital diagram, and give th

natta225 [31]

Answer:

1. Orbital diagram

2p⁴ ║ ↑↓ ║ "↑" ║ ↑

2s² ║ ↑↓ ║

1s² ║ ↑↓ ║

2. Quantum numbers

n = 2,
l = 1,

$m_{l}$ = 0,

$m_{s}$ = +1/2

Explanation:

The fill in rule is:

Follow shell number: from the inner most shell to the outer most shell, our case from shell 1 to 2

Follow the The Aufbau principle, 1s<2s<2p<3s<3p<4s<3d<4p<5s<4d<5p<6s<4f<5d<6p<7s<5f<6d<7p
Hunds' rule: Every orbital in a sublevel is singly occupied before any orbital is doubly occupied. All of the electrons in singly occupied orbitals have the same spin (to maximize total spin).

So, the orbital diagram of given element is as below and the sixth electron is marked between " "

2p⁴ ║ ↑↓ ║ "↑" ║ ↑

2s² ║ ↑↓ ║

1s² ║ ↑↓ ║

The quantum number of an electron consists of four number:

n (shell number, - 1, 2, 3...)
l (subshell number or orbital number, 0 - orbital s, 1 - orbital p, 2 - orbital d...)
$m_{l}$ (orbital energy, or "which box the electron is in"). For example, orbital p (l = 1) has 3 "boxes", it was number from -1, 0, 1. Orbital d (l = 2) has 5 "boxes", numbered -2, -1, 0, 1, 2
$m_{s}$ (spin of electron), either -1/2 or +1/2

In our case, the electron marked with " " has quantum number

n = 2, shell number 2,
l = 1, subshell or orbital p,

$m_{l}$ = 0, 2nd "box" in the range -1, 0, 1

$m_{s}$ = +1/2, single electron always has +1/2

3 0

4 years ago

A 100-watt light bulb radiates energy at a rate of 100 J/s. (The watt, a unit of power or energy over time, is defined as 1 J/s.

Semmy [17]

Answer

2.7956 * 10^19 photons

Givens

Wavelength = λ = 525 * 10^-9 meters [1 nmeter = 1*10^-9 meters]
c = 3 * 10^8 meters
E = ???
W = 100 watts
t = 1 second
h= plank's Constant = 6.26 * 10^-34 J*s

Formula

E = h * c / λ

W = E / t

Solution

E = 6.26 * 10^-34 j*s * 3 * 10^8 m/s /525 * 10^-9 (m)

The meters cancel out. So do the seconds. You are left with Joules as you should be.

E = 3.577 * 10^-18 Joules

What you have found is the energy of 1 photon.

Now you have to find the Joules from the watts.

W = E/t

100 * 1 second = 100 joules

1 photon contains 3.577 * 10 ^ - 18 Joules

x photon = 100 joules

1/x = 3.577 * 10^-18 / 100 Cross multiply

100 = 3.577 * 10 ^ - 18 * x Divide both sides by 3.577 * 10 ^ - 18

100/3.577 * 10 ^ - 18 = 3.577 * 10 ^ - 18x / 3.577 * 10 ^ - 18

2.7956 * 10^19 photons = x

7 0

3 years ago

The atomic masses of any two elements contain the same number of

den301095 [7]

Answer:

They contain of atoms

Explanation:

That's because atomic weights or masses of each atom of each element are proportional to each other, the same number of atoms of each element will give masses that are also proportional to each other. If you start with 20 oxygen atoms, you will need 40 hydrogen atoms to make the water and you will get 20 molecules of water.

8 0

3 years ago

Help please

andrew11 [14]

Answer:

K2Cr2O7

Explanation:

Solubility refers to the amount of substance that dissolves in a given mass or volume of solvent. There are several units of solubility applicable in different areas.

Solubility is dependent on temperature. The solubility curve is a graphical representation of the dependence of solubility on temperature for different chemical species.

If we study the solubility curve closely, we will see that K2Cr2O7 has the highest solubility at 100°C. This means that if the trends continue, this substance will also have the highest solubility at 120°C.

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3 years ago

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Salt is the product formed by a reaction in which _______ atoms of an acid are replaced by the atoms of a metal.

UkoKoshka [18]

Salt is the product formed by a reaction in which the hydrogen atoms of an acid are replaced by the atoms of a metal. The salt is formed as a result of the neutralization of the acid by base, that is the metal or positive ion replace the hydrogen ion in the acid. For instance: NaO + H2SO4 = NaSO4 + H2O. In this example, Na [sodium] has replaced the hydrogen in H2SO4, thereby forming the salt NaSO4.

7 0

3 years ago

Read 2 more answers