Atomic Mass

Sulfur- Element Number 16 on the Periodic Table of Elements

42

because

The atomic number of calcium is 20. The atomic number stands for the number of protons in an element. It is represented by the letter Z.

There isn't one, but there is an element with the atomic mass of 200.59 and that is Hg for mercury with an atomic of 80.

that's easy.

32 neutrons means that the mass of protons is 25 (as is the electrons) so all i have to do is look for the right one.

simlpy thinking there are 2e (2 electrons on te inner shell) ten each one afterwards has up 8e unless there are no more electrons to fill the shell.

in this case its like this:

2e, 8e, 8e, 7e.

the element is infact manganese in group 5 (Mn).

magnese will react with anything from group one easily at a 1:1 basis and will react with anything from group 2 at a 2:1 basis (the 2 representing magnese).

PlutOnium 239 is an element - plutOnium - with an atomic weight of 239.

Name: Boron
Symbol: B
Atomic Number: 5
Atomic Mass: 10.811 amu
Melting Point: 2300.0 °C (2573.15 K, 4172.0 °F)
Boiling Point: 2550.0 °C (2823.15 K, 4622.0 °F)
Number of Protons/Electrons: 5
Number of Neutrons: 6
Classification: Metalloid
Crystal Structure: Rhombohedral
Density @ 293 K: 2.34 g/cm3
Color: brownish

density=mass/volume

1mL=1cm^3, so 30.0 mL=30.0 cm^3

then you divided the volume 30.0 by the mass 81.0 grams is euqal to 81.0 grams/30.0 cm^3=2.7 g/cm^3(that's the units)

An atomic mass unit, also known as AMU, is the unit used to measure the weight of protons and neutrons. If an element has an atomic mass of 84 AMU, that element has a total of 84 protons and neutrons in its nucleus.

The atomic mass unit is approximately the mass of one neutron or proton. An electron has a mass of approximately 1/2000 of an amu.

90.7 amu

One mole of atoms of an element is equal to the atomic mass of that element expressed in grams.

Nitrogen-14

so one mole of nitrogen weighs 14 g

Daltons experiments with gases also led him to form two more chemical laws, the Law of Partial Pressures (behaviour of gaseous mixtures and dissolving of gases into liquids) and the Law of Multiple Proportions (ratios and gas composition). It is needless to say that without Dalton's work and consequent theories, Chemistry as we know it today may not exist.

If you mean "how does one determine an atoms atomic mass?", then the answer would be to find a periodic table of elements where the whole numbers indicate atomic number and the other indicating atomic mass. Atomic number is generally described as the number of protons in a naturally occurring atom of a given element, and the atomic mass is the number of protons + number of neutrons in an atom.

The atomic number of krypton is 36, and its atomic weight from the periodic table is 83.798.

Refer to the related links for a printable periodic table.

As it ids an average the more abundant will have a greater net effect than the least abundant.

This entirely depends on the percentage of the different isotopes present. This is typically determined through mass spectrometry. After the percentages of the different isotopes are known, one times the percentage of each isotope by its relative atomic mass, then add this all together. After dividing this by 100, you will have attained the average atomic mass of a naturally ocurring element.

The atomic weight given on the periodic table is "average" weight of a sample of the element including it most common isotopes. Since the isotopes can have different weights, when one averages the weights, the number is a little off.

Sometimes the atomic mass is listed as the average mass of the isotopes and contains a decimal. But since you can't have a fractional part of a proton or a neutron without creating a big mess, it is necessary to round to the nearest whole number. Subtracting the atomic number from the rounded atomic mass will give you the number of neutrons.

This reason is, simply, very obvious. Compare the numbers: 238 and 16. Since the orbitals are more full, and the nucleus is packed tighter, and Uranium is located after atomic number 84, it is unstable. All of the elements after 84 are unstable. But that doesn't count isotopes of the earlier elements, because they can be unstable.

Mass number = Number of protons + Number of neutrons

For the isotope 241Am the mass number is 241; for 242Am is 242, for 243Am is 243, etc.

Americium has isotopes with mass numbers that range from 231 through 249.

Nitrogen has a gram atomic mass of 14.0067, an atomic number of 7, and the chemical symbol N.