The chemical properties of an element are determined by the charge of
its nucleus, i.e. by the
number of protons . This number is
called the
atomic number and is denoted by the letter
Z .
Atomic number (Z)
The number of protons in an atom
You can find the atomic number on the periodic table. The atomic number is an integer and ranges from 1 to about 118.
The mass of an atom depends on how many nucleons its nucleus contains.
The number of nucleons, i.e. the total number of protons
plus neutrons,
is called the
atomic mass number and is denoted by the letter
A .
Atomic mass number (A)
The number of protons and neutrons in the nucleus of an atom
Don't confuse the notation we have used above with the way this information appears on the Periodic Table. On the Periodic Table, the atomic number usually appears in the top lefthand corner of the block or immediately above the element's symbol. The number below the element's symbol is its
relative atomic mass . This is not exactly the same as the atomic mass number. This will be explained in
"Isotopes" . The example of iron is shown below.
You will notice in the example of iron that the atomic mass number is more or less the same as its atomic mass. Generally, an atom that contains
n nucleons (protons and neutrons), will have a mass approximately equal to
u. For example the mass of a
atom which has 6 protons, 6 neutrons and 6 electrons is 12u, where the protons and neutrons have about the same mass and the electron mass is negligible.
Use standard notation to represent sodium and give the number of protons, neutrons and electrons in the element.
Sodium is given by
Sodium has 11 protons, so we have:
Sodium has 12 neutrons.
In standard notation sodium is given by:
. The number of protons is 11, the number of neutrons is 12 and the number of electrons is 11.
The structure of the atom
Explain the meaning of each of the following terms:
Complete the following table: (Note: You will see that the atomic masses on the Periodic Table are not
whole numbers . This will be explained later. For now, you can round off to the nearest whole number.)
Bacteria doesn't produce energy they are dependent upon their substrate in case of lack of nutrients they are able to make spores which helps them to sustain in harsh environments
_Adnan
But not all bacteria make spores, l mean Eukaryotic cells have Mitochondria which acts as powerhouse for them, since bacteria don't have it, what is the substitution for it?
Assimilatory nitrate reduction is a process that occurs in some microorganisms, such as bacteria and archaea, in which nitrate (NO3-) is reduced to nitrite (NO2-), and then further reduced to ammonia (NH3).
Elkana
This process is called assimilatory nitrate reduction because the nitrogen that is produced is incorporated in the cells of microorganisms where it can be used in the synthesis of amino acids and other nitrogen products
There are nothing like emergency disease but there are some common medical emergency which can occur simultaneously like Bleeding,heart attack,Breathing difficulties,severe pain heart stock.Hope you will get my point .Have a nice day ❣️
_Adnan
define infection ,prevention and control
Innocent
I think infection prevention and control is the avoidance of all things we do that gives out break of infections and promotion of health practices that promote life
