1 A patient is diagnosed with thyroid cancer. Which isotope is used to treat the patient? flag bookmark A Carbon-14 B Sodium-24 C Cobalt-60 D Iodine-131 T4 Chapter 2.4 Isotopes and Its Uses The thyroid gland absorbs iodine, so radioactive iodine-131 collects there and destroys the cancer cells.
2 The following information is about atom T. - Number of protons is 3 - Nucleon number is 7 Which diagram shows the structure of atom T? flag bookmark A B C D T4 Chapter 2.3 Atomic Structure T has 3 protons and 7 − 3 = 4 neutrons in the nucleus, and 3 electrons arranged 2.1. Only A shows 3p + 4n with electrons 2.1.
3 An atom of element E has 20 neutrons. The nucleon number of element E is 39. Atom E donates electrons to form ion E. How many electrons are in ion E? flag bookmark A 18 B 19 C 20 D 21 T4 Chapter 2.3 Atomic Structure Protons = 39 − 20 = 19 (2.8.8.1). E donates its single valence electron to form E⁺, which has 19 − 1 = 18 electrons.
4 The following equation represents a chemical reaction. $$\text{Na}_2\text{CO}_3(aq) + \text{CaCl}_2(aq) \rightarrow \text{CaCO}_3(s) + 2\text{NaCl}(aq)$$ Which statement is correct? flag bookmark A Two moles of sodium carbonate react with one mole of calcium chloride B The products are solid calcium carbonate and sodium chloride solution C The reactants are solid sodium carbonate and calcium chloride solution D Two moles of calcium carbonate and one mole of sodium chloride are formed T4 Chapter 3.4 Chemical Equation The state symbols show the products are solid CaCO₃ (s) and aqueous NaCl (aq). The ratio is 1 : 1 : 1 : 2, and both reactants are aqueous.
5 Table 1 shows the electron arrangements of elements W, X, Y and Z. | Element | Electron arrangement | |---|---| | W | 2.4 | | X | 2.8 | | Y | 2.8.2 | | Z | 2.8.7 | Which element is a metal? flag bookmark A W B X C Y D Z T4 Chapter 4.2 The Arrangement in the Periodic Table of Elements Y (2.8.2) has 2 valence electrons and is in Group 2 — magnesium, a metal. W is carbon, X is neon and Z is chlorine.
6 Diagram 1 shows the position of element Y in the Periodic Table of Elements. Which of the following are the characteristics of element Y? I Dissolves in water II Forms coloured compounds III Has a low melting point IV Has more than one oxidation number flag bookmark A I and II B I and III C II and IV D III and IV T4 Chapter 4.7 Transition Elements Y is in the middle block, so it is a transition element. Transition elements form coloured compounds and have more than one oxidation number; they have high melting points and do not dissolve in water.
7 Table 2 shows the proton numbers of elements W, X, Y and Z. | Element | W | X | Y | Z | |---|---|---|---|---| | Proton number | 3 | 6 | 11 | 12 | Which arrangement shows the atomic size of the elements in descending order? flag bookmark A Z, Y, X, W B W, X, Y, Z C X, W, Z, Y D Y, Z, W, X T4 Chapter 4.2 The Arrangement in the Periodic Table of Elements Y (Na) and Z (Mg) have 3 shells, W (Li) and X (C) have 2. Within each period, size decreases across: Na > Mg > Li > C, i.e. Y, Z, W, X.
8 Which compound is formed by transferring electrons? flag bookmark A Oxygen, $\text{O}_2$ B Sodium oxide, $\text{Na}_2\text{O}$ C Carbon dioxide, $\text{CO}_2$ D Hydrogen peroxide, $\text{H}_2\text{O}_2$ T4 Chapter 5.2 Ionic Bond Sodium oxide is an ionic compound formed when sodium atoms transfer electrons to oxygen atoms. The others are covalent.
9 Table 3 shows the electron arrangements of element Y and element Z. | Element Y | Element Z | |---|---| | 2.4 | 2.6 | What is the formula and the type of bond of the compound formed from the reaction between Y and Z? | | Formula | Type of bond | |---|---|---| | A | $\text{YZ}_2$ | Covalent | | B | $\text{YZ}_2$ | Ionic | | C | $\text{Y}_2\text{Z}$ | Covalent | | D | $\text{Y}_2\text{Z}$ | Ionic | flag bookmark A A B B C C D D T4 Chapter 5.3 Covalent Bond Y (2.4, carbon) needs 4 electrons and Z (2.6, oxygen) needs 2, so one Y shares electrons with two Z atoms: $\text{YZ}_2$, a covalent compound.
10 Which pair of acids is classified correctly? | | Monoprotic acid | Diprotic acid | |---|---|---| | A | Ethanoic acid | Hydrochloric acid | | B | Hydrochloric acid | Ethanoic acid | | C | Sulphuric acid | Nitric acid | | D | Nitric acid | Sulphuric acid | flag bookmark A A B B C C D D T4 Chapter 6.3 Strength of Acids and Alkalis Nitric acid (HNO₃) releases one H⁺ per molecule (monoprotic); sulphuric acid (H₂SO₄) releases two (diprotic).