chemistry class 10

Which of the following sets of elements do not belong to the same group?

• Na,K,Rb

• P,S,CI

• C,Si,Ge

• F,CI,Br

Which of the following belongs to group 18?

• I

• Rb

• Sr

• Ar

Which of the following has largest atomic size?

• O

• C

• Be

• F

According to IUPAC recommendations, the number of groups in the long form of the periodic table is:-

• 7

• 18

• 16

• 9

Which is not true about the noble gases?

• They are radioactive in nature

• • They are non metallic in nature
  • 
    

• • Xenon is the most reactive among these

•  They exist in atomic form

The least metallic element of group I is:-

• Lithium

• • Potassium

• Caesium

• Sodium

Which of the following pairs of elements does not belong to same group?

• Cl

  .

  Br

• N. P

• Al, Si

• Mg, Ca

Which of the following statement is not correct about the trends when going from left to right across the periodic table?

• The number of valence electrons increases

• the oxides become more acidic

• The elements become less metallic in nature

• The atoms lose their electrons more easily

Which of the following has the lowest number of electrons in the valency shell?

• O

• B

• N

• C

Formula of bleaching powder

• CaSO4

• Na2CO3

• NaHCO3

• CaOCl2