Atomic structure of phosphorus

Introduction
Phosphorus is an element of Group 15 and period 3. Its symbol is P having atomic number 15 and mass number 31. It belongs to p- block elements. It is a non- metal. Its electronic configuration is
[Ne]3S² 3P³

It generally exists in two forms, white phosphorus and red phosphorus. It is very reactive so it is not found in Free State in nature. White phosphorus emits light or glows when exposed to air or oxygen.

Atomic structure of phosphorus

Atomic number of phosphorus is 15 and thus its electronic configuration is 2,8,5. So it has following atomic structure.It has 2 electrons in K shell, 8 in L and 5 in M shell.

Image of phosphorus and its structure

Properties of phosphorus

Luminsecence is the main property of phosphorus. This property can be defined as the ability to emit light or glow in dark. Allotropes.

Phosphorus has two common allotropes called white phosphorus and red phosphorus. Red phosphorus is an intermediate phase between white and violet phosphorus. White phosphorus is most reactive and least stable form of all allotropes of phosphorus. It is insoluble in water. Two radioactive isotopes of phosphorus have half-lives that make them useful for scientific experiments. ³²P has a half-life of 14.262 days and ³³P has a half-life of 25.34 days. Phosphorus can expand its valence electron to make penta- and hexavalent compounds eg phosphorus chloride molecule.

Most common Oxidation states of Phosphorus are 5, 4, 3, 2, 1 , -1, -2, -3

The first, second and third Ionization energies of phosphorus are as follows
1011.8 kJ·mol⁻¹, 1907 kJ·mol⁻¹ and 2914.1 kJ·mol⁻¹.As per Pauling scale the Electronegativity of phosphorus is 2.19.

Preparation of phosphorus by Brand’s process

Phosphorus is not found in the native state in nature as it is reactive. So it can be prepared by Brand's process by using sand in the reaction

4 NaPO₃ + 2 SiO₂ + 10 C → 2 Na₂SiO₃ + 10 CO + P₄

Phosphate rock is the main source of phosphorus. It is made up of tri-calcium phosphate mineral called apatite.

Conclusion for the atomic structure of phosphorus

From the discussion, we conclude that phosphorus is a non metal having atomic number 15 and is reactive. It has 5 valence electrons in its outermost shell so it needs 3 more electrons to complete the octet. So it is reactive.

Atomic structure of Nickel

Introduction :
Nickel was accidentally discovered by Axel F Cronstendt when he was trying to isolate the element from its mineral ore kupfernickel in Sweden taking it to be copper. Nickel is mostly available in the pentlandite [(Ni, Fe)9S8] and garnierite ores found in countries like South Africa, Russia, Australia and Canada. It was discovered 250 years ago. It is the fifth most abundant element on earth.

Structure for Atomic structure of Nickel

Nickel is a group 10 element and is one of the transition elements holding an atomic number of 28. With an atomic number 28, nickel has 28 electrons in various energy levels or these electrons are distributed in the orbitals of the atom.

As the atomic number of nickel is 28 it has 28 protons and 28 electrons. It has 31 neutrons in the atom's nucleus. The electrons assigned to different orbitals are 2, 8,16,2. The electron configuration of nickel can be written as 1s2 2s2p6 3s2p6d8 4s2 . The only Ferro-magnetic elements are nickel, iron & cobalt and among them nickel is supposed to be least magnetic.

Atomic structure of Nickel – properties and uses

Properties:

Nickel is corrosion resistant but it is soluble in acids. Alkalis do not affect Nickel though. 58.6934is the atomic mass of nickel. 2732 degree Celsius is its boiling point. 1453 degree Celsius is its melting point. 6.59 cm³/mole is its molar volume. Its density is 8.9g/cc.

Uses of Nickel:

Electroplating and for formation of metal alloys nickel is used because of its resistance to corrosion. It is also used as catalyst in nickel-cadmium batteries. It is also the main constituent in coins. Because of durability, strength and corrosion resistance nickel alloys are the most sought after compared to other alloys. In animals, nickel along with iron plays an important role of transporting oxygen in blood. It is part of enzyme functioning in plants & animals. Whole grains such as oats are excellent source of nickel. It is also part of genetic code DNA & RNA. In many cordless appliances, nickel-cadmium batteries are commonly used.

Conclusion for Atomic structure of Nickel

As per the discussion on atomic structure of nickel, we came to know that, other metals can be used in place of nickel and one more reason is its cost effectiveness, nickel is the most preferred metal.

Magnesium atomic weight

Introduction :
Atomic weight is the mass of an atom expressed in Atomic Mass Units (amu). An atomic mass unit is equal to one-twelfth of the mass of a carbon atom of the isotope C-12.

An atom consists of subatomic particles electrons, protons, and neutrons. Protons and neutrons have equal mass of 1 amu, whereas electrons have negligible mass. So for the atomic weight of an element, we do not consider the mass of electrons.

Atomic weight = Number of nucleons.
'Nucleons' is the term for protons and neutrons.
Atomic weight is represented by the letter 'Z'.

Thus, if there are 7 protons and 7 neutrons in the nucleus of an atom, then its atomic weight will be
Z = 14 amu.

Atomic weight of magnessium:

Electronic configuration
The magnesium atom has 12 protons and 12 neutrons in its nucleus. Therefore magnesium atomic weight is Z = 24 amu. The following diagram shows a magnesium atom. It's nucleus contains 12 protons and neutrons and it is surrounded by 3 orbits having 2, 8 and 2 electrons respectively.

Position in periodic table
Magnesium is located in the 3^rd period of the periodic table. It is the second element of group 2 of the periodic table.

Reactivity
Magnesium is a highly inflammable metal. To stop a “magnesium-fire”, the only option is to put sand on the burning magnesium so as to avoid its contact with the atmosphere. Magnesium owes this behavior to the fact that it burns in oxygen, nitrogen, carbon dioxide as well as water vapor also.

Magnesium has a valency of 2. It loses two electrons to form positive ions during its chemical reactions. Thus, the majority of chemical reactions undergone by magnesium are ionic in nature, and it mostly forms ionic compounds. It reacts slowly with water at room temperature, releasing Hydrogen gas bubbles. It also reacts with most acids in an exothermic reaction.

Other properties
Most magnesium compounds are white in color and soluble in water, giving it a slightly sour taste due to Mg2+ ions. The commercially important Magnesium minerals are dolomite, magnesite, brucite, carnallite, talc, and olivine. Magnesium is present in ocean water as salts of its compounds, and this way it is the second most abundant metal present in ocean water. Also, Magnesium is the seventh most abundant element in the earth's crust.

Magnesium properties and uses

Physical properties

• Magnesium is a silvery white metal. It is strong, light-weight and ideal for making machines. Since magnesium cannot react with atmospheric oxygen on exposure to air, it is used as alloy in building machines and structures.
• Magnesium also has a high tensile strength and thus it is ideal to use in building structures.
• Magnesium is ductile, and can be cut very easily. On the other hand, its resistance to deformation is higher than most other metals. Furthermore, it is not brittle to impact, and thus, it is highly siutable fot construction of lagre buidings and structures.
• Magnesium has a high shock absorbing capacity, and is a good conductor of heat. It is resistive to time and temperature and can be cut, welded, molded very easily. Thus, it is an ideal metal for machine making also.
• Magnesium compounds when dissolved in water taste sour due to the presence of magnesium ions (Mg2+)

Chemical properties

• It is reactive to air, and tarnishes in the presence of atmospheric oxygen. However, on reaction with air, it forms a protective covering of magnesium oxide on its surface, which prevents further reactions of the metal. Thus, magnesium can be stored in normal environment. Formation of oxide: `Mg + O2 -gt 2MgO`
• Magnesium reacts with water at room temperature, though the reaction stops after a short time because of the formation of the insoluble Magnesium Hydroxide. Reaction: `Mg + H2O -gt Mg(OH)2 + H2`
• Magnesium burns in steam to form its oxide and Hydrogen gas. Reaction: `MG + H2O (steam) -gt MgO + H2`
• Magnesium also reacts with acids like Hydrochloric acid to produce its Chloride, liberate Hydrogen and heat (it is an exothermic reaction). Reaction: `Mg + 2HCl -gt MgCl2 + H2`
• Magnesium burns in air with a brilliant white light. It is reactive with Oxygen, Nitrogen, Carbon dioxide and also water vaopour in air, and thus it is difficult to distingiush a magnesium fire. Reaction of Magnesium with oxygen and nitrogen: `2Mg + O2 -gt2MgO`
        `3Mg + N2 -gt Mg3N2`
  

Uses

• It is used in the manufacture of automobile and truck components.
• It is widely used in making race cars, since it is a light, resistant metal.
• It is also widely used in the manufacturing of electronic devices like cell phones, laptops, etc.
• Magnesium was widely used in the construction of air crafts.
• Used in incendiary weapons in firebombin of cities in WWII
• Milk of magnesia is sometimes used as an antacid, as it is a mild base.
• Magnesium is used in photography to produce flares of brilliant white light, and is also used in fireworks for sparklers.

Atomic number 93

Introduction 

• From periodic table Atomic number 93 is ‘Neptunium’.
• Chemical symbol is ‘Np’.
• Neptunium as atomic number is 93 and mass number is 237.0482
• Neptunium belongs to f-block element because the atom has valence electron in f-orbital.
• f-block elements are also called inner transition elements.
• In Neptunium the outermost electrons are in 5f-orbitals
• Neptunium atom belongs to actinide series. 
• It has electronic configuration [Rn], 7s², 6d¹, 5f²
• It occurs in solid state in nature.
• Atomic number 93 was discovered by Edwin Mcmillan and Philip H.  Abelson in the year 1940 in Berkeley, California.
• Trace amount of Neptunium are naturally found as a decay product from transmutation reaction in uranium ores.

 Sources of Neptunium
Np is most often extracted from spent nuclear fuel rods as a by-product of plutonium production.
Artificial ²³⁷Np is produced through the reduction of ²³⁷NpF₃ with barium or lithium vapour at 1200⁰C.
     2NpF₃    +    3Ba    →    2Np    +    3BaF₂
When uranium atom is bombarded with slow moving neutron, ²³⁹Np was produced.  It was first transuranium element.  At the time 23 minute.  Elimination of β^- particle occurs, Neptunium is obtained.
      ₉₂U²³⁸ + ₀n¹  →  ₉₂U²³⁹  →  ₉₃Np²³⁹

Properties of Atomic number 93

• Neptunium element has density 20.45g/cm³.
• It has melting point 910K and high boiling point of 4273K.
• It has oxidation state 7, 6, 5, 4, 3.
• Atomic number 93 has atomic radius 155pm.
• Neptunium has three crystal structure forms.

Half life of Np

There are nineteen  neptunium radioisotopes which have been characterized, with the most stable being ²³⁷Np with a half-life of 2.14 million years, ²³⁶Np with a half-life of 154,000 years, and ²³⁵Np with a half-life of 396.1 days. All of the remaining radioactiveMeta states, with the most stable being ²³⁶Np which as half life of 22.5 hours. isotopes have half-lives which have less than 4.5 days, and the majority of these have half-lives that are less than 50 minutes. This element also has 4

Synthesis of Atomic number 93
When a ²³⁵U atom captures a neutron, it is converted to an excited state of ²³⁶U. About 81% of the excited ²³⁶U nuclei undergo fission, but the remainder decay to the ground state of ²³⁶U by emitting gamma radiation. Further neutron capture creates ²³⁷U which has a half-life of 7 days and thus quickly decays to ²³⁷Np through beta decay. During beta decay, the excited ²³⁷U emits an electron, while the atomic weak interaction converts a neutron to a proton, thus creating ²³⁷Np.
    ₉₂U^{235 +} ₀n¹    → ₉₂Um²³⁶    →  ₉₂U²³⁶  + γ
    ₉₂U²³⁶  +  ₀n¹    →  ₉₂U²³⁷      →  ₉₃Np²³⁷

Uses of Atomic number 93

• ²³⁷Np is irradiated with neutrons to create ²³⁸Pu, an alpha emitter for radioisotope thermal generators for spacecraft and military applications. ²³⁷Np will capture a neutron to form ²³⁸Np and beta decay with a half life of two days to produce ²³⁸Pu.

      ₉₃Np²³⁷ + ₀n¹ → ₉₃Np²³⁸  →  ₉₄Pu²³⁸

• Np is fissionable, and could be theoretically be used as fuel in a fast neutron reactor or nuclear weapon.
• ²³⁷Np is used in devices for detecting high-energy (MeV) neutrons.

John Dolton chemistry

Introduction
John Dalton law was proposed by John Dalton in the year 1801. According to this law at a particular temperature, the total pressure of a mixture of two or more non-interacting gases is equal to the sum of partial pressures of the individual gases.
This law can be mathematically written as:
P_total = P₁ + P₂ + P₃ + ...
Here P₁, P₂, P₃ are the partial pressures of each component in the mixture.

John Daltons Atomic Theory, Laws of multiple proportions, Dalton’s law of partial pressure and for Daltanism.  Dalton concluded that evaporated water exists in air as an independent gas in the course of his studies.  Dalton found that evaporation might be viewed as a mixing of water particles with air particles. He performed a series of experiments on mixtures of gases to determine what effect properties of the individual gases had on the properties of the mixture as a whole and he was the first to associate the ancient idea of atoms with stoichiometry.  Dalton came to know the vital theoretical connection between atomic weights and weight relations in chemical reactions. The core concepts of Dalton’s theory are foundations of modern physical science.


                   John Dolton

Assumptions of John Dolton chemistry

All matter consists of tiny particles
Atoms are indestructible and unchangeable: According to this assumption of John Dalton atoms of an element cannot be created, destroyed, broken into smaller parts or transformed into atoms of another element. So he stated that atoms cannot be created, destroyed or transformed into other atoms in a chemical change.

Elements are characterized by the mass of their atoms: According to this assumption atoms of different elements have different weights.

When elements react their atoms combine in simple, whole number ratios:  In this postulate Dolton explained that compounds contained characteristic atom-to-atom ratios in this postulate he effectively explained the law of definite proportions.

When elements react, their atoms sometimes combine in more than one simple, whole-number ratio:  According to this postulate why the weight ratios of nitrogen to oxygen in various nitrogen oxides were themselves simple multiples of each other.

Atoms in compounds according to John Dalton Chemistry

The law of fixed composition

Conservation of matter and energy

Introduction
The conservation of matter and energy means that the total amount of energy and the total amount of matter is always constant in a given closed, isolated system. In other words, neither energy nor mass can be created or destroyed in any physical or chemical process.

Formation of the law of conservation of matter and energy

Until the discovery of mass - energy equivalence by Albert Einstein in 1905, conservation of matter and conservation of energy were two different conservation laws. Conservation of matter implied that matter can neither be created nor destroyed, and conservation of energy implied that energy can neither be created nor destroyed. The two were not related to each other in any  aspect except that they were both conversations laws.
But, as physics and science increased its parameters with the advance of technology,nuclear reactions were discovered, and it was discovered that in nuclear fusion and fission reactions, the total mass of reactants does not equal to the total mass of the products obtained. For example, in the following nuclear fusion reaction,
4H → 2He,
There is a difference between the mass of the reactants, that is, four atoms of Hydrogen, and the mass of the products, that is, one atom of Helium. This difference can be clearly depicted by the following diagram:-



The difference in the mass could not be explained by any laws, and furthermore, it was a direct failure of the law of conservation of mass. Huge amount of energy was produced in the above reaction, and this "creation" of energy and in was certainly a setback to the law of conservation of energy. But in 1905, Albert Einstein pointed out that in the chemical reactions like above, the difference in mass of the reactants and products is balanced by the release of energy, that is, some mass of the reactants was converted into energy, and since matter and energy are the same thing, conversion of matter into energy cannot be regarded as the creation of energy. He also gave the formula to calculate the amount of energy produced as follows:-
`e = mc^2` .

Conservation of Matter and Energy : Albert Einstein

Albert Einstein pointed out that matter and energy are the same thing, and matter can be converted to energy. Thus, if energy is being "produced" in a nuclear reaction, although the total calculated amount of energy is increasing, but since the calculated amount of mass is decreasing, and matter and energy are the same thing, therefore the total energy of the system can be regarded as constant.
Thus, the law of conservation of energy and the law of conservation of matter were combined, to form the law of conservation of matter and energy. Note that the term "The Law of Conservation of Energy" implies the law of conservation of matter and energy.

Conservation of Mechanical energy

Introduction :
Conservation of mechanical energy states that the whole mechanical power (sum of kinetic energy+ potential energy) of a structure remains stable provided the forces acting on the body are conservative. The standard of conservation of mechanical energy states, the whole mechanical energy of a conservation system leftovers constant.

Proof of Conservation of Mechanical energy

Suppose a particle of mass m moves from position x₁ to another position x₂ under the action of conservation force. As a result its velocity changes from v₁ to v₂. By work-energy theorem, we have

If V₁ and V₂ are the potential energies at positions x₁ and x₂, we have

If effort done by a conservative force is positive, the kinetic energy of body increases and potential energy of body decrease to stay total mechanical energy conserved.

Example of Freely Falling Body

Gravitational force is conservation force. When a body of mass m, initially at rest at height H, above the ground, falls under gravity, then its total mechanical energy remains constant.

At heighest point A:
The body is at rest, therefore kinetic energy,

Potential energy, V=mgh
Total mechanical energy at A=K+V=0+mgH=mgH

At point B:
Let the body reach at intermediate point B at distance x below point.

Potential energy=mg(H-x)

At point C:
Let C be the point on the ground. If v_C is the velocity at point C, then relation
V²=u²+2gs gives v²_C =0 +2gH=2gH
Kinetic energy,

Potential energy = 0
Total mechanical energy at C=mgH=0=mgH
Thus it is clear that for a freely falling body, the total mechanical energy remains constant.

Example of Mass-Spring System in Conservation of Mechanical Energy

Consider a spring-block system located on a horizontal frictionless table. Mass of block is M and force stable of spring is K. when mass is in position A, spring is in its usual length. So that elastic PE of spring is zero. When mass is taken to position B, the spring is stretched by an amount x₀, so elastic potential energy of spring (= (1/2 )kx₀²) and kinetic energy in this position = zero.