The complex compound formed by the combination of two elements with a large electronegativity difference is likely to be
- A. polar covalent
- B. giant molecular
- C. covalent
- D. ionic
The shape of a graphite crystal is
- A. tetrahedral
- B. pyramidal
- C. hexagonal
- D. octahedral
Which of the following halogens is liquid at room temperature?
- A. Chlorine
- B. Fluorine
- C. lodine
- D. Bromine
Which of the following elements is a metalloid?
- A. Carbon
- B. Oxygen
- C. Silicon
- D. Sodium
Which of the following statements about a radioactive substance is/are correct? l. lt emits radiation continuously and spontaneously. ll. The emitted radiations are affected by temperature and pressure III. The radiation can penetrate opaque matter
- A. ll only
- B. l and ll only
- C. l and lll only
- D. ll and lll only
The d-block elements are paramagnetic because they
- A. contain paired electrons which are repelled by magnetic field
- B. contain unpaired electrons in the partially filled 3d-orbital
- C. contain paired electrons which are repelled by magnetic field force
- D. have delocalized valence electrons
Two elements, X and Y are in the same group on the periodic table because they both have the same
- A. number of electronic shells
- B. number of valence electrons
- C. atomic size
- D. atomic number
The atomic radii of metals are usually
- A. greater than their ionic radii
- B. equal to their ionic radii
- C. less than their ionic radii
- D. less than those of non-metals in the same period
Which of the following ions has an electron configuration different from the other?
- A. 17CI-
- B. 8O2-
- C. 12Mg2+
- D. 13AI3+
Which of the following electron configurations represents that of an atom in its ground state?
- A. 1s 22s12p1
- B. 1s22s22p63s13p1
- C. 1s22s12p3
- D. 1s22s22p63s0
The number of orbitals in a p-sub level of an atom is
- A. 2
- B. 3
- C. 5
- D. 6