Elements and Compounds

Ferrous sulphate is FeSO4 ; Iron (II) sulphate

Do NOT confuse with Ferric Sulphate , which is ' Fe2(SO4)3 '; Iron(III) sulphate

In Ferrous compounds iron is in Oxid'n state '2' (II). Green in colour

In Ferric compounds iron is in Oxid'n state '3' (III). Red/brown in colour.

NB THe oxid'n number is ALWAYS quoted in Roman Numerals.

Yes, energy is released in a sodium and chlorine reaction as they form sodium chloride (table salt) due to the formation of new chemical bonds which are more stable than the individual sodium and chlorine atoms. This release of energy is typically in the form of heat.

' +6'

To calculate the oxidatioin state. use oxygen at '-2' as the standard.

There being four oxygen atoms in SO4^(2-)

Then the oxygen moiety is 4 x -2 = -8

Since the overall charge on the anion is ;-2'

We create a little sum

S + -8 = -2

S - 8 = -2

Add '8' to both sides

S = -2 + 8

S = +6 (The oxidation state of sulphur in SO4^(2-) .

NB Sulphur has variable oxidation states, ranging from -2,0,2,4, & 6.

NNB The oxidation number indicates the number of electrons in the valence(outermost) shell involved in bonding. Not all electrons in the valence shell are used in bonding.

This method is good for calculating other oxidation states. e.g. potassium manganate (VII) : KMnO4.

What is the oxidation state of manganese. ? It is ;7; (VII).

How do we go there>

Again remeber oxygen at '-2' and the manganese anion is MnO4^(-)

So 4 x -2 = -8

Create the sum

Mn + - 8 = -1 (The charge on the anion).

Add '8' tpo both sides.

Mn = -1 + 8

Mn = 7 (The oxidation state of manganese in MnO4^(-) .

NNNB All oxidation numbers are quoted as Roman Numerals. . Hence S is (VI) ' 6' and Mn is (VII) '7'.

YES!!!

However, it has to be heated up .

All elements and nearly all compounds can exist in solid liquid or gaseous state.

The critical factors for changes of state are temperature and gas pressure above the substance.

NB Carbon dioxide (gas) sublimes directly to a solid (dry ice) when cold enough. However, this is atmospheric gas pressure. If the gas pressure is altered then it can be converted to a liquid.

Beryllium.

Its full electron configuration is ' 1s2, 2s2 , '.

It depends on the type of plastic and the type/strength of the acid.

Many plastics such as polyethylene (PE) and polypropylene (PP) are resistant to many common acids.

Some plastics can react, weaken, dissolve, crack, or degrade when exposed to strong acids or certain chemical conditions.

for more://nsda.gov.bd/pages/files/6922db73933eb65569e0a326

Yes, EXTRASHADE sunscreen is very helpful for men, women.

It protects your beautiful Rich complexions from the harmful UV rays of the sun.

the equation is correct but some time scientist say there will be byproduct of glycerin is also obtained

In simple terms it is an hydrogen atom , consisting of one proton and one electron. The electron having been ionised off, to leave a 'charged proton' (symbolised as 'H^(+) '.)

However, in aqueous solutions, this 'loose' proton attached itself to the 'lone pair' on a water molecule, to form the ion ' H3O^(+) '.

Having a sexual fantasy about a family member can be unsettling and may evoke feelings of guilt or confusion. These fantasies can arise from a variety of psychological factors, including a complex mix of emotions and desires. It's important to recognize that fantasies do not necessarily reflect one's real-life feelings or intentions. If these thoughts cause distress, it might be helpful to speak with a mental health professional for guidance.

Phosphorus is NOT in Group '3' . It is Group '5' , with nitrogen.

However, it is in Period '3' (Third Row). of the Periodic Table.

Neon(Ne) is an INERT /NOBLE gas. It does not react with anything.

It exists as monatomic atoms.

Its atomic structure is ; -

Protons. 10

Electrons ; 10

Neutrons ; 10 ( commonest isotope).

Its atomic No, is '10'.

Its Atomic Mass is ; 20. ( 10 protons + 10 neutrons = 20 nucleons).

Argon(Ar) is an INERT /NOBLE gas. It does not react with anything.

It exists as monatomic atoms.

Both gases are found in the Periodic Table, in Group(18)/Noble Gases.

Its atomic structure is ; -

Protons. 18

Electrons ; 18

Neutrons ; 22 ( commonest isotope).

Its atomic No, is '18'.

Its Atomic Mass is ; 39.9. ( 18 protons + 22 neutrons = 40( ~39.9 nucleons).

Hydrogen is the only combustible element, other elements, need an interaction with "something else" other than its self to be combustible.

Therefore Hydrogen is the only "fuel". Fuel such as gasoline have bonds to Hydrogen that bulk it up, slow it down, and generally make Hydrogen dense.

Solid CO2 is known as 'Dry Ice'.

Carbon dioxide is a COMPOUND, composed of two elements viz. Carbon and oxygen.

The composition of this compound is

1 x carbon

2 x oxygen

Hence its formula ' CO2 '.

Any two or more different atoms combined together form a COMPOUND.

e.g. Water ( H2O ) is a compound

Methane ( CH4 ) is a compound

Ammonia ( NH3 ) is a compound.

New elements that are synthesised in a lab. are usually given a name of a scientist , or the place where they are first synthesised.

Have a look in the Periodic Table, at the Trans-Uranic elements. .

e.g. Californium ; first synthesised in California (USA) or 'Fermium' after Enrico Fermi , an Italian scientist. et.se

NB Most pre-trans-uranic elements occur naturally.

The name of the substance says it all. viz. Calcium and Bromine.

There are NO other elements present.

CaBr2 .

That is :-

1 x Calcium (Ca)

2 x Bromine(Br) [ as the bromide anion (Br^(-)) ] .

Yes!!!!

MgO (Magnesium oxide ) is a base, because it is a Group 2 metallic oxide.

An Alkali is a soluble base.

So if MgO is dissolved in water it forms the alkali magnesium hydroxide.

MgO(s) + H2O(l) = Mg(OH)2(aq)

NB Note the use of brackets in Mg(OH)2. This indicates that there are two hydroxide anions in the molecule. Writing as MgOH2 (No brackets) is INCORRECT, because it only indicates 1 x oxygen present , when there are actually 2 x oxygens in the molecule.

MgO + 2HCl = MgCl2 + H2O

The products are magnesium chloride and water.

When hydrochloric acid and magnesium carbonate react, they produce magnesium chloride, carbon dioxide, and water. The balanced chemical equation for this reaction is: 2HCl + MgCO3 → MgCl2 + CO2 + H2O.

CaCO3 + SiO2 ==Heat==> CaSiO3 + CO2

The products are calcium silicate and carbon dioxide.

When calcium carbonate is heated it undergoes thermal decomposition, to form calcium oxide(CaO) and carbon dioxide.

CaO is a base , because it is a metallic (Group 2) oxide. It reacts with SiO2 , which is an acidic oxide ( because it is a non-metallic (Group 4) oxide.

Remember a base plus an acid form a 'salt'. in this case CaSiO3 .

NB This is the side reaction going on in a blast furnace during iron oxide reduction. The reason for adding the 'flux' calcium carbonate (CaCO3) to remove the silicon dioxide impurity in the iron oxide.

NNB The carbon dioxide (CO2) is NOT released into the atmosphere, but undergoes reduction in excess coke (carbon) to form carbon monoxide (CO), which is the reducing agent of iron ore in the blast furnace.

Chlorine is the halogen that is in the same period as potassium. They are both in period 3 of the periodic table.

The halogens with their period no. are :-

Fluorine (2)

Chlorine (3)

Bromine (4)

Iodine (5)

Astatine (6)

Tennessine (7)

The last two are radio-active and not fully characterised. You will not find them in a school/college lab.

NB There are NO halogens in period '1'. The only elements in period '1' are hydrogen(H) and helium(He).

Under to process of electron affinity , they readily form anions.

As elements they are coloured. Yellow, green, brown, black/indigo, black.

As elements on going down the group they range from gas to liquid to solid. That is their m.p. & b.p. become higher on going down the group.

Do not conduct electricity

Poisonous.

They are all strongly electronegative

They all form 'chemical salts' with cationic metals. e.g. sodium chloride

The name 'halogen' means 'salt maker/generator' , and is from Classical Greece.