Page 31 - PRE-U STPM CHEMISTRY TERM 1

Chemistry Term 1 STPM
11 What is the proton number of an element that has 17 Which of the following elements has 5 unpaired
6 unpaired electrons in its ground state? electrons in its ground state?
A 14 C 24 A Nitrogen
B 22 D 30 B Phosphorous
C Manganese
12 The lines in the emission spectrum of hydrogen D Iron
are the results when CHAPTER
A electrons are removed from the atom. 18 Which of the following valence configuration is 2
B electrons absorb energy. for an atom that can form positive ions of different
oxidation state?
C electrons lose energy. A 3d 4s C 3d 4s 2
10
10
1
D the hydrogen molecules split to form atoms. B 3s 3p D 3d 4s 2
1
1
2
13 Part of the lines in the Lyman series of an emission 19 Which of the following species would have a line
spectrum of atomic hydrogen is shown below. spectrum similar to that of the hydrogen atom?
A He 2+ C Na +
B Li D K +
2+
X 20 Which of the following statements is not true?
Which of the following statements is not true? A 3d orbitals have the same energy as the 4s
orbital.
A The lines have frequencies corresponding to B p orbitals are filled with electrons according
ultra-violet radiation to Hund’s rule.
B The wavelength of line X can be used to C The principle quantum number of p orbitals
calculate the ionisation energy of hydrogen start with n = 2.
C Each line corresponds to electronic transition D An s orbital is spherical.
between higher energy levels and level n = 1
D The hydrogen atom has 6 electrons 21 An atom X has six valence electrons and forms a
3+
stable X ion. In which group of the Periodic
14 In a hydrogen atom, electron in which orbital can Table does X belong to?
absorb energy but cannot emit energy? A 3 C 13
A 1s C 3s B 6 D 16
B 2p D 3d

22 The proton number for species X is 8 and its
15 Which of the following electronic transitions nucleon number is 18. Species X has two electrons
would emit visible light of highest frequency? less than the number of neutron. What is the
A n → n
4 2 charge on X?
B n → n
2 6 A 0 C +1
C n → n B –1 D +2
5 1
D n → n 2
1
23 Which of the following electronic arrangements
16 Which statement is not true about the s, p and d violates Hund’s rule?
orbitals? A
A The five d orbitals have the same shape and
same energy B
B The three p orbitals have the same shape and
same energy C
C In any energy shell, the energy of the orbitals
increases in the order s < p < d D
D d orbitals are directional whereas s orbitals
are non-directional

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02 Chapter 2.indd 61 3/26/18 3:14 PM