Elements and Compounds

Yes, all samples of water have the same composition of hydrogen and oxygen, with each water molecule containing two hydrogen atoms and one oxygen atom. This is consistent regardless of the source or location of the water.

The Carbonate anion has four atoms.

1 x carbon

3 x oxygen

Giving the formula ' CO3^(2-)' It does NOT exists in its own right as a substance, but in combination with a metal. e.g. CaCO3 Calcium carbonate.

As many as you like!!!!!

Different substances have a different number of hydrogen atoms in their formula.

e.g.

Water ; H2O ; 2 hydrogen atoms

Ammonia ; NH3 ; 3 hydrogen atoms.

Methane ; CH4 ; 4 hydrogen atoms.

The polymer 'polypropylene' can have millions of hydrogen atoms.

NO such substance as ' h3po4 '.

If you mean ' H3PO4 '. , then there are eight(8) atoms.

3 atoms of hydrogen

1 atom of phosphorus ( '1' is never shown in chemical formulae ).

4 atoms of oxygen .

3 + 1 + 4 = 8

NB When writing formula, single letter elemental symbols are ALWAYS a CAPITAL letter.

Hence hydrogen is 'H' ; not 'h'

phosphorus is 'P' ; not 'p'

Oxygen is 'O' , not 'o'

This is the international IUPAC standard and as shown in the Periodic Table.

It is done to avoid confusion between say ' CO' and 'Co'. which are two different substances.

Two letter elemental symbols are written as , first letter is a CAPITAL letter and the second letter is small/lower case. e.g. ' Na ' sodium '.

So ' h3po4 ' is totally incorrect and meaningless.

ONE (1)

The formula ' H3PO4 '. tells that there are ;=

3 atoms of hydrogen

1 atom of phosphorus ( '1' is never shown as a number in any substance).

4 atoms of oxygen .

The numbers are written sub-script after the given elemental symbol.

First of all H3PO4 is NOT an Element.

It is a compound, composed of three elements viz., hydrogen , phosphorus, and oxygen.

H3PO4 is phosphoric acid .

protium and deuterium are both isotopes of hydrogen.

A third isotope of hydrogen it 'tritium' . This isotope contains 1 proton , 2 neutrons. So it is three times as heavy as a single proton.

Tritium atomic structure is ;- 1 proton , 2 neutrons and 1 electron. It has an atomic mass of '3'.

You will not find it readily available anywhere, because it is a 'radio-active gas', and has to be securely contained.

The state symbol for copper sulphate solution is:

CuSO

4

​

(aq)

​

(aq) means aqueous, which means the copper sulphate is dissolved in water.

If it is solid copper sulphate, it is written as CuSO₄(s).

If it is dissolved in water as a solution, it is CuSO₄(aq).

When two or more compounds are mixed together, they do not undergo a chemical reaction to form new substances. Each compound maintains its own chemical identity and properties. This is a physical change rather than a chemical change.

You can also have sodium chloride , or potassium carbonate.

Any ionic substance, when dissolved in water is an electrolyte.

No such compound as 'caci'.

If you mean

CaCl2 then it is calcium chloride.

Note the use of capital letters and numbers.

No such compound as NAC10

You

'Na' need to clarify the formula.

'N' = nitrogen

'A' = There is no element with a single capital letter 'A'.

'C10' = Ten Carbons ?????? .

If you mean ' NaClO'. This is sodium chlorite.

Note the use of small case letters

'Na' is sodium (nadium)

'Cl' is chlorine '( lower case 'l' , NOT '1').

'O' is oxygen

Hydrogen gas (H₂) is held together by a single covalent bond.

That means the two hydrogen atoms share one pair of electrons. Each hydrogen atom needs 2 electrons to have a full outer shell, so by sharing electrons, both atoms become more stable.

So the answer is:

A single covalent bond holds two hydrogen atoms together in hydrogen gas.

You have answered the question for yourself.

The formula is C12H22O11

The number after each elemental symbol , tells of the number of atoms of that element in the molecule.

Hence

Carbon (C) has 12 atoms

Hydrogen (H) has 22 atoms

Oxygen (O) has 11 atoms.

YES!!!Its a 'big' complex molecule. Unfortunately, I cannot draw it in Answers to show the atomic arrangements.

Boron has three valance electrons. Boron also has three electtrons in outermost energy shell.

The 'Valance' number of electrons tells you how many bonds will form between boron and other atoms.

Compare with oxygen . Oxygen has two valance electrons . However, oxygen has 6 electrons in its outermost energy shell. This means that oxygen will form two bonds between other atoms. Thus leaving four electrons uncombined; they are known as 'lone pairs'.

Because the electrons are fixed their given bond, and are NOT free to move.

When electrons are free to move within a substance then it is conducting electricity.

In Diamond , electrons are not free to move. ], because each carbon atom creates four single covalent bonds , with each of its four neighbour carbon atoms, in an Adamantine Structure.

However, in Graphite, each carbon atom creates three bonds with neighbour carbon atoms. This leaves a 'spare' electron that can move. Hence graphite conducts electricity,; as in carbon brushes in electrical motors.

Diamond and Graphite are two of the three allotropes of carbon. One conducts electricity , but the other resists conduction.

As a solid metal oxide , it is a BASE.

When dissolved in water it is an ALKALI.

Remember an Alkali is a soluble BASE.

metal oxide + water = metal hydroxide.

NB THere is NEITHER a gas, NOR metal salt produced.

General Group '1' metal

M2O + H2O = 2MOH

General eq'n fro Group '2' meta;

MO + H2O = M(OH)2

'M' refers to the metal from the given Periodic Table Groups.

Elemental carbon as the graphite allotrope is 'BLACK'.

As Diamond, it is an opaque white-ish rock, until 'cut' by a jeweller. Then clear and shiny.

Buckminster fullerene(C60) ??? red/orange.

These are the three known allotropes of elemental carbon .

'NO' Nitric Oxide.

Do NOT confuse with

N2O ; Nitrous Oxide (Laughing gas)

NO2 ; Nitrogen dioxide.

NO3^(-) ; nitrate anion.

Every element is found in the environment.

However, not all elements are found as elements, but generally in combination with other elements.

'Gold' is a notable exception. It is found/mined/panned as nuggets.

Any acid (x) .

Remember the general reaction equ'n for acids and carbonates.

Acid + Carbonate = Salt + Water + Carbon Dioxide.

So using hydrochloric acid (HCl)

2HCl + CaCO3 = CaCl2 + H2O + CO2

The 'salt' is calcium chloride (CaCl2)

Using Ethanoic(Acetic ) Acid

2CH3COOH + CaCO3 = Ca(CH3COO)2 + H2O + CO2

The salt is calcium ethanoate(acetate) Ca(CH3COO)2

Remember the general acid reaction eq'n.s

Acid + Base = Salt + Water

Acid + Alkali = Salt + Water

Acid + Metal = Salt + hydrogen

Acid + Carbonate = Salt + Water + Carbon Dioxide.

NB An Alkali is a soluble Base.

Yes!!!! It's named 'WATER' (H2O).

NB Compounds are any substances where two or more different elements combine together.

Carbon dioxide (CO2) is a compound

Sodium chloride (NaCl) is a compound

Ammonia (NH3) is a compound.

etc.,

There millions more compounds.

Depending on the temperature, hydrogen can exist in three states of matter (forms), viz., gas, liquid, and solid.

Also hydrogen has three isotopes, viz. protium, deuterium, and tritium. This depends on the number of neutrons present in the nucleus.

protium ; 0 neutrons ; The most common isotope of hydrogen

deuterium ; 1 neutron ; known as 'heavy hydrogen'.

tritium ; 2 neutrons ; known as 'super-heavy' hydrogen, and it is also radio-active.

NB When describing as 'forms' you need to be more specific, re. isotopes, states of matter , or any other characteristic.

YES!!! It is an isotope named 'Tritium'.

hydrogen exists as three isotopes.

#1; protium ; 1 proton, 0 neutrons, 1 electron ; Atomic mass '1'. The most common isotope of hydrogen

#2; deuterium ; 1 proton, 1 neutron, 1 electron ; Atomic mass '2'. Known as 'heavy' hydrogen

#3 tritium ; 1 proton, 2 neutrons, 1 electron ; Atomic mass '3'. The rarest isotope and radio active isotope of hydrogen

Notice the number of neutrons in each isotope, and also the atomic mass increases.

NB THe next element in the Periodic Table is Helium (He)

He ; 2 protons, 2 neutrons and 2 electrons. Atomic Mass '4'. The most inert element known.

Again compare hydrogen/helium regarding number of protons, neutrons, and electrons, and atomic mass.