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प्रश्न
Write an explanation.
Period
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उत्तर
A period is a horizontal row in the periodic table where elements have the same number of electron shells and show a gradual change in properties across the row.
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संबंधित प्रश्न
Fill in the blank:
The modern periodic table consists of ……………. periods.
Nitrogen (atomic number 7) and phosphorus (atomic number 15) belong to group 15 of the Periodic Table. Write the electronic configuration of these two elements. Which of these will be more electronegative? Why?
Write the names given to the vertical columns and horizontal rows in the Modern Periodic Table. How does the metallic character of elements vary on moving down a vertical column? How does the size of atomic radius vary on moving left to right in a horizontal row? Give reason in support of your answer in the above two cases.
What is periodicity in properties of elements with reference to the Modern Periodic Table?
Why do all the elements of the same group have similar properties?
Fill in the following blank with suitable word:
Group 17 elements are known as ...............
How were the positions of cobalt and nickel resolved in the modern periodic table?
Would you place the two isotopes of chlorine, CI-35 and CI-37 in different slots because of their different atomic masses or in the same slot because their chemical properties are the same? Justify your answer.
Is it possible to have an element having atomic number 1.5 placed between hydrogen and helium?
The three elements having chemical symbols of Si, B and Ge are:
(a) all metals
(b) all non-metals
(c) all metalloids
(d) Si is metalloid, B is metal and Ge is non-metal
The atomic numbers of four elements P, Q, R and S are 6, 8, 14 and 16 respectively. Out of these, the element known as metalloid is:
(a) P
(b) Q
(c) R
(d) S
Which of the following statement is correct in regard to the classification of elements?
(a) Elements in modern periodic table are arranged on the basis of increasing atomic masses.
(b) Elements in Mendeleev's periodic table are arranged on the basis of increasing atomic numbers.
(c) In modern periodic table, the element nickel of lower atomic mass is kept before the element cobalt of higher atomic mass.
(d) In modern periodic table, the isotopes of chlorine having different atomic masses are kept in the same group.
The atomic particle whose number in the atoms of an element always remains the same and which forms the real basis for the modern classification of elements is:
(a) electron
(b) proton
(c) neutron
(d) meson
What is the fundamental difference in the electron configurations between the group 1 and group 2 elements?
Explain why, the first period of the periodic table has only two elements whereas second period has eight elements
In the modern Periodic Table, why does cobalt with higher atomic mass of 58.93 appear before nickel having lower atomic mass of 58.71?
What are the periods in a periodic table? Give two characteristics of each.
State the term
The tabular arrangement of elements in horizontal rows and vertical columns _________
Name two elements in halogens.
Write the number of protons, neutrons and electronic configuration of \[\ce{_19^39K, _15^31P}\]. Also state their position in periodic table.
Write a short note.
Position of isotopes in the Mendeleev’s and the modern periodic table.
How does number of (i) valence electrons (ii) valency; vary on moving from left to right in the second period of a periodic table?
Give the symbol and valency of the following element and radical.
Nitrogen [Nitride]
Give the symbol and valency of the following element and radical.
Hydroxide
Give the symbol and valency of the following element and radical.
Carbonate
State what is meant by the term chemical formula.
Give the chemical formula of sodium hydroxide
Give the chemical formula of calcium phosphate
State the number of elements in Period 2 of the Periodic Table.
How were elements arranged in the long form of the periodic table or the Modern Periodic Table?
Right or wrong sentence.
The modern periodic table shows the molecular masses of the elements in each frame.
Which of the given elements A, B, C, D and E with atomic number 2, 3, 7, 10 and 30 respectively belong to the same period?
Which of the following is the outermost shell for elements of period 2?
Which one of the following elements exhibit maximum number of valence electrons?
Group 16 elements are collectively called as ______.
A part of modern periodic table is given below. On its basis, answer the following questions:
| Group No. → | 1 | 2 | 13 | 14 | 15 | 16 | 17 | 18 |
| Period ↓ | ||||||||
| 2 | A | B | ||||||
| 3 | E | D | F | C |
Which of the element is a Noble gas?
- Write the electronic configuration of element X, given by its symbol as under: \[\ce{^40_20 X}\]
- Determine its position in the modem periodic table.
- What is the nature of its oxide?
- Name one other element of its group.
Give the criteria on the basis of which elements are placed (i) in a group and (ii) in a period in the modern periodic table. The atomic number of an element is 16. According to the criteria, in which group and period it should be placed?
Define periods of modern periodic table.
