Periodic Table

For example manganese, with an electronegativity after Pauling of 1,55.

Hidrogen explodes when ignited if it's in the presence of oxygen.

Francium has 87 protons, and mass numbers ranging from 199 to 232, with the longest lived isotopes having mass numbers of 221 to 223. There are different decay modes for the different isotopes, and without knowing the isotope, we cannot produce an equation.

Metals (and also transition metals are considered even though they aren't in specific families, they are the same as any other metal, nothing special.)

It decreases. This is because each period (row) you go down, the element has more shells. The more shells the less effective the positive nucleus is at attracting other negative atoms to bond with and gain an electron. It is made harder to attract because there is an increasingly bigger field of negative electrons in the way.

Sodium has only one valence electron, and when that is donated to some other atom, the remaining ion has a noble gas configuration that is highly stable. Disrupting that by another ionization requires much energy. Magnesium has two valence electrons; therefore the second is almost as easy to donate as the first. The third ionization enthalpy of magnesium would be very high.

Safety match heads contain minuscule amounts of potassium chlorate, as an oxidizer. When a match is struck, the friction generated between the match head and the box is sufficient to ignite the red phosphorus. Again sufficient heat is generated to prompt the decomposition of the potassium chlorate in the head. At this point the extra oxygen aids the fuel in the match stick and the wood itself catches fire.

Metal carbonates are chemical compounds composed of a metal cation and a carbonate anion. The most common metal carbonate is calcium carbonate, found in substances like limestone and chalk. Metal carbonates typically react with acids to produce carbon dioxide gas, water, and a metal salt.

It is supposed to be mol/dm-3

Actually, 1 dm cube is the same as 1 litre.

Therefore, there is no need of conversion. Both are the same.

The "expected" answer is helium, neon, and argon, BUT

-- in 2000 there was a claim that the first argon compound had been made

-- no compounds of elements 99 and above are really "known", since most of these elements last less than an hour, and have never been made in quantities of more than a few atoms at a time. We "know" of many compounds that must exist, and have a very good sense of what their properties are, but compounds have not actually been prepared and characterized.

-- it is very doubtful that any francium compound has been isolated and characterized, although those of the other very unstable lighter elements promethium, astatine, actinium, and protactinium have been.

1. Iron (Fe) - used in construction materials, vehicles, and machinery.
2. Oxygen (O) - essential for respiration and combustion processes.
3. Silver (Ag) - used in jewelry, electronics, and photography.
4. Hydrogen (H) - used in fuel cells, refining processes, and ammonia production.

Explore key information about the chemical elements through this periodic table Group 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Period 1 1
H 2
He 2 3
Li 4
Be 5
B 6
C 7
N 8
O 9
F 10
Ne 3 11
Na 12
Mg 13
Al 14
Si 15
P 16
S 17
Cl 18
Ar 4 19
K 20
Ca 21
Sc 22
Ti 23
V 24
Cr 25
Mn 26
Fe 27
Co 28
Ni 29
Cu 30
Zn 31
Ga 32
Ge 33
As 34
Se 35
Br 36
Kr 5 37
Rb 38
Sr 39
Y 40
Zr 41
Nb 42
Mo 43
Tc 44
Ru 45
Rh 46
Pd 47
Ag 48
Cd 49
In 50
Sn 51
Sb 52
Te 53
I 54
Xe 6 55
Cs 56
Ba * 71
Lu 72
Hf 73
Ta 74
W 75
Re 76
Os 77
Ir 78
Pt 79
Au 80
Hg 81
Tl 82
Pb 83
Bi 84
Po 85
At 86
Rn 7 87
Fr 88
Ra ** 103
Lr 104
Rf 105
Db 106
Sg 107
Bh 108
Hs 109
Mt 110
Ds 111
Rg 112
Cp 113
Uut 114
Uuq 115
Uup 116
Uuh 117
Uus 118
Uuo *Lanthanoids * 57
La 58
Ce 59
Pr 60
Nd 61
Pm 62
Sm 63
Eu 64
Gd 65
Tb 66
Dy 67
Ho 68
Er 69
Tm 70
Yb **Actinoids ** 89
Ac 90
Th 91
Pa 92
U 93
Np 94
Pu 95
Am 96
Cm 97
Bk 98
Cf 99
Es 100
Fm 101
Md 102
No

I presume that by "elements" you are meaning simple substances in elemental form, not in compounds.

It is also important to note that the price of any material depends very much on how pure you want it to be, and how much of it you want to contract to buy.

There is also a lot of difficulty in comparing prices of gases with those of solids or liquids, because with gases there is often also a cost of cylinder hire, and high delivery/collection costs. For the purposes of this answer I shall leave out gases. I think they would all be more expensive than the cheapest solid or liquid elements, but it is very hard to work out the comparison. And there are complications: for nitrogen, do you base the price on compressed gas or on liquid nitrogen. For oxygen hire of a generating machine is usually a better and safer option than a compressed gas cylinder, but how do you cost that?

For gases I think (not at all sure) that the order would go nitrogen(cheapest) < oxygen < hydrogen < chlorine about same as argon, and others much more expensive.

For non-gaseous elements, I found that the best comparison was for high quality industrial grade materials (typically 95 to 99.5% purity) in quantities around 1 tonne.

The cheapest 3 seem to be sulfur, carbon, and iron, all in the 15¢/kg to 50¢/kg range.

Aluminium, lead, and zinc are similarly priced, around $2/kg, with silicon (~$2.50), magnesium (~$3.00), and manganese (~ $ 3.50) just a little higher.

That leaves a tenth slot, that probably goes to some common element that I am overlooking. Failing that, it seems we have to go to copper, at about $7.50/kg

There is no group number to Uranium though its group name is Actinide.

The region containing mostly elements that are gases at room temperature is the rightmost column, known as the noble gases or Group 18. These elements have full outer electron shells, making them stable and non-reactive, which allows them to exist as gases at room temperature.

That's not a very valid question becase you could argue that all the elements in that particular group are important. There are at least 4 common ones there, which are carbon, silicon, lead, and tin.

By finding the atomic number minus the group number

1- Solubility in water.. Sugar is soluble but Copper is not.

2- Conductivity.. Copper is conductor of electricity but sugar is not.

3- Colour.. Copper is pinkish but sugar is white.

There are several other properties which may be used to distinguish between copper and Sugar.

Iodine really does not possess much in the way of metallic nature at all. It is very definitely a non-metal. The only characteristic metallic property it possesses is that the solid is a dark grey colour with a somewhat lustrous sheen. It looks a bit like a metal. But that is where the metallic character stops. The solid is very brittle -- not at all plastic or resilient like a metal. It is a very poor conductor of electricity. Its oxides are difficult to form, and they are all acidic rather than basic. The ion that it most readily forms has a single negative charge, like those of chlorine and bromine. Metals only form positively charged ions.

In N2, there is a stron triple bond between the two nitrogens which require large amount of energy to break. Hence it is less reactive.

In P4, there is single bonds between the different phosphorus atoms and it easy to break and hence P4 is more reactive.

Dmitri Mendeleev left gaps in the periodic table to account for elements that had not been discovered yet. He predicted the properties of these missing elements based on the patterns he observed among known elements. This led to the successful discovery of new elements that filled in the empty spaces, validating his periodic table.

Periods on the periodic table go across and are based on the number of unexcited electrons increasing as you read across. Groups on the periodic table are read down the table and share the same number of valence electrons.

Fluorine has the smallest atomic radius of all the p-block elements. This is because as you move across a period from left to right, the atomic radius decreases due to increasing nuclear charge pulling the electrons closer to the nucleus.

Some internationally recognized symbols for elements include H for hydrogen, O for oxygen, Fe for iron, Na for sodium, and Au for gold. These symbols are derived from the element's name in English, Latin, or Greek.