Answer:
Explanation:
The <em>periodic table</em> shows the elements ordered by atomic number in an arragement of 18 columns and 7 rows.
The atomic number is the number of protons of the elment and this identifies each element unequivocally.
Thus, once you know the atomic number you just need to locate the element in the periodic table and read the symbol and other data.
Other important definition that you need to know is:
- Mass number = number of protons + number of neutrons
You also should know that the row represents the period of the element (which is the main energy level in the quantum model of the atom), and the column represents the group (e.g. grouo 1 = alkali metals, group 18 = noble gases).
<u>1) A: atomic number</u>
The first cell of the first row of the given table indicates that the number of protons is 4.
Then, per definition atomic number = number of protons = 4.
<u>2) B: mass number</u>
The mass number, A, of an element is equal to the number of protons (Z) plus the number of neutrons (N).
From the table: A = 4 and N = 2. Thus:
- Mass number = Z = 4 + 2 = 6
<u>3) C: element (symbol)</u>
Once, you know the number of protons (atomic number), you just need to locate the element in the table.
You will find that the element with the atomic number 4, is in the period (row) 2 and group (column) 2.
Its chemical symbol is Be and its name is berillyum.
<u>4) D: number of protons</u>
This is the next row of your table.
In the fourth cell of this secon row you can read that the atomic number is 10.
Then, as indicated above, per definition, the atomic number is the number of protons.
Thus, the number of protons is 10.
<u>5) E: mass number</u>
As said previously, the mass number is equal to the number of protons (Z) plus the number of neutrons.
You have:
- Number of protons = atomic number = 10
- Mass number = 10 + 12 = 22
<u>6) F: element (symbol).</u>
In the periodic table, you locate the element with atomic number 10 in the column 18 (group of the noble gases) and the period (row) 2.
The element is neon and its chemical symbol is Ne.
