Periodic Table Section

Here are the solutions to your questions:

1. Periodic Table Section

a) Using the letters from the table, select an element that is:

• i) Stored in paraffin oil. Alkali metals (Group 1) are highly reactive and stored in paraffin oil. Element A is in Group 1. Answer: $\boxed{A}$
• ii) A reddish liquid at RTP. Bromine is a reddish-brown liquid at room temperature. Bromine is in Group 17, Period 4. The elements F (Group 17, Period 2) and G (Group 17, Period 3) are not Bromine. None of the elements A-H shown in the table fit this description. Answer: None of the elements shown

b) Write the electronic configuration of:

• i) B: Element B is in Group 2, Period 2. This corresponds to Beryllium (Be), which has an atomic number of 4. Electronic configuration: $\boxed{2, 2}$ (or $1s^2 2s^2$)
• ii) Why is B classified in group II? Element B is classified in Group II because it has $\boxed{two \text{ valence electrons}}$ (two electrons in its outermost electron shell).

c) The element, E, has a relative atomic mass of 27. Give the composition of an atom of E.
If the relative atomic mass of element E is 27, then E is Aluminum (Al). Aluminum has an atomic number of 13.

• i) Number of protons: The atomic number equals the number of protons. Answer: $\boxed{13}$
• ii) Number of electrons: For a neutral atom, the number of electrons equals the number of protons. Answer: $\boxed{13}$
• iii) Number of neutrons: The number of neutrons is calculated by subtracting the number of protons from the relative atomic mass. $$\text{Number of neutrons} = \text{Relative atomic mass} - \text{Number of protons}$$ $$\text{Number of neutrons} = 27 - 13 = 14$$ Answer: $\boxed{14}$

d) Two elements X and Y have atomic numbers of 6 and 17 respectively.

• Element X (atomic number 6) is Carbon (C).
• Element Y (atomic number 17) is Chlorine (Cl).
• i) Write the formula of the compound formed between X and Y. Carbon (Group 14) typically forms 4 covalent bonds. Chlorine (Group 17) typically forms 1 covalent bond. To satisfy the valencies, one carbon atom will bond with four chlorine atoms. Formula: $\boxed{CCl_4}$
• ii) Identify the bond type in the compound in d(i) above. Carbon and Chlorine are both non-metals. The bond formed between two non-metals is a covalent bond. Bond type: $\boxed{Covalent \text{ bond}}$

e) Sodium chloride has the formula NaCl. Identify the charge of the metallic ion:
In Sodium chloride (NaCl), Sodium (Na) is the metallic ion. Sodium is in Group 1 and loses one electron to form a stable ion.
Charge of the metallic ion: $\boxed{+1}$ (or $Na^+$)

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2. Elements and Reactions

Given elements: Sodium (Na), Silver (Ag), Calcium (Ca), Iron (Fe), Aluminium (Al).

a) Select from the elements:

• i) A transition metal used as a catalyst. Iron (Fe) is a transition metal commonly used as a catalyst (e.g., in the Haber process). Answer: $\boxed{Iron \text{ (Fe)}}$
• ii) An element that forms an amphoteric oxide. Amphoteric oxides react with both acids and bases. Aluminium (Al) forms an amphoteric oxide ($Al_2O_3$). Answer: $\boxed{Aluminium \text{ (Al)}}$
• iii) An element that is a basic constituent of bones. Calcium (Ca) is a major component of bones, primarily in the form of calcium phosphate. Answer: $\boxed{Calcium \text{ (Ca)}}$

b) Arrange the elements in order of decreasing reactivity, starting from the most reactive.
Based on the reactivity series, the order from most reactive to least reactive is:
Order: $\boxed{Sodium \text{ (Na)}, Calcium \text{ (Ca)}, Aluminium \text{ (Al)}, Iron \text{ (Fe)}, Silver \text{ (Ag)}}$

c) The element Calcium (Ca) reacts with dilute hydrochloric acid.

• i) State one common observation. Calcium is a reactive metal that reacts with acids to produce hydrogen gas. Observation: $\boxed{Effervescence \text{ (fizzing or bubbling)}}$
• ii) Write a balanced equation for the reaction taking place. Calcium reacts with hydrochloric acid to form calcium chloride and hydrogen gas. $$\boxed{Ca(s) + 2HCl(aq) \to CaCl_2(aq) + H_2(g)}$$