The force of attraction between covalent molecules is?
- A. electrostatic attraction
- B. hydrogen bonding
- C. ionic force
- D. van der Waals forces
Water molecules are held together by
- A. covalent bond
- B. hydrogen bond
- C. ionic forces
- D. van der Waals forces
Arrange the following elements in order of increasing electron affinity: Br2CI2
I 2
F 2
- A. I 2CI2Br2F 2
- B. I 2Br2CI2F 2
- C. CI2 I 2Br2F 2
- D. Br2CI2 I 2 F 2
Consider the following elements and their electronic configurations
W: 1s22s2
X: 1s 22s22p6
Y: 1s22s22p63s2
Z: 1s22s22p63s23p2. Which of the elements belong to the same group in the periodic table?
- A. W and X only
- B. Y and Z only
- C. W and Y only
- D. W, Y and Z only
Elements in the same group of the periodic table have
- A. the same number of valence electrons
- B. the same number of electron shells
- C. different chemical behaviour
- D. the same atomic size
Which of the following statements is not true of halogens?
- A. they exist in different physical states
- B. they exist as diatomic molecules
- C. their ionic radii decrease down the group
- D. their melting and bolling points increase down the group
Atom \(^{234} _{88} Q\) decay by alpha emission to give an atom R. The atomic number and mass number of atom R are respectively
- A. 86 and 230
- B. 87 and 234
- C. 88 and 233
- D. 90 and 238
What is the atomic number of an element whose cation Y+ has the electronic configuration 1s22s22p6?
- A. 9
- B. 10
- C. 11
- D. 12
The valence electrons in a chloride ion are [17CI]
- A. 2p electrons only
- B. 3s and 3p electrons only
- C. 3p and 3d electrons only
- D. 3p electrons only
Find the number of neutrons in an atom represented by 4521X.
- A. 21
- B. 24
- C. 45
- D. 66
The mass spectrometer can be used to measure mass of
- A. an atom
- B. an electron
- C. a proton
- D. a neutron