Advertisements
Advertisements
प्रश्न
Right or wrong sentence.
The size of an atom depends on the number of valence electrons.
विकल्प
Right
Wrong
Advertisements
उत्तर
The given sentence is wrong.
Explanation:
Atomic size is determined mainly by the principal quantum number (which shell the valence electrons occupy) and by effective nuclear charge and shielding, not simply the count of valence electrons. Atoms down a group get a new shell, so size increases, while across a period, added electrons stay in the same shell, but higher nuclear charge pulls them closer, so size decreases.
संबंधित प्रश्न
Arrange the following as per the instruction given in the brackets:
Na, K, Li (Increasing atomic size)
Arrange the elements of second and third periods in increasing order of their atomic size (excluding noble gases).
Study the radius of the element given below and answer the following questions.
| elements | K | Na | Rb | Cs | Li |
| Atomic radius (pm) | 231 | 186 | 244 | 262 | 151 |
a) Which of the above elements have the smallest atom?
b) In which group of the modern periodic table the above element are belongs?
c) What is the periodic trend observed in the variation of atomic radii down a group?
Among the elements of the second period, Li to Ne, pick out the element with the largest atomic size
Fill in the blanks.
Size of the atoms ______ from left to right across a period and ______ on descending in a group of normal elements.
Select the correct answer
Atomic radii of fluorine and neon in angstrom unit are
The following questions refer to the Periodic Table.
What happens to the atomic size of elements moving from top to bottom of a group?
The metals of Group 2 from top to bottom are Be, Mg, Ca, Sr and Ba. Which one of these elements will form ions most readily and why?
Fill in the blank by selecting the correct word from the bracket.
If an element has seven electrons in its outermost shell then it is likely to have the _____ atomic size among all the elements in the same period.
_______ is the distance between the nucleus of the atom and its outermost shell.
Right or wrong sentence.
Nanometer unit is used to measure atomic radius.
Write an explanation.
Atomic radius
Write scientific reason.
In same period, boron and oxygen elements have different atomic size.
The electronic configuration of metal A is 2, 8, 18, 1.
The metal A when exposed to air and moisture forms B a green layered compound. A with con. H2 SO4 forms C and D along with water. D is a gaseous compound. Find A, B, C, and D.
Which of the following is the correct order of size?
Which of the following gives the correct increasing order of the atomic radii of O, F and N?
Which of the following are the characteristics of isotopes of an element?
- Isotopes of an element have same atomic masses
- Isotopes of an element have same atomic number
- Isotopes of an element show same physical properties
- Isotopes of an element show same chemical properties
- In below ladder symbols of elements are jumbled up. Rearrange these symbols of elements in the increasing order of their atomic number in the Periodic Table.
- Arrange them in the order of their group also.
The diagram below shows part of the periodic table.
- Which elements would react together to form covalent compounds?
- Between the two elements W and Z, which will have a bigger atomic radius? Why?
Arrange the following in order of increasing radii:
Cl−, Cl
Explain your choice.
