Question

1 which property shows an increasing trend in the elements, from group i to group vii, across a period of the periodic table? a ability to form anions b metallic character c number of electron shells d reactivity with water 2 the melting point of lithium is 181°c. the melting point of sodium is 98°c. which statement explains why lithium has a higher melting point than sodium? a lithium has more valency electrons than sodium. b sodium is more reactive than lithium. c sodium is softer than lithium. d the attraction between the positive ions and the sea of electrons is stronger in lithium than in sodium. 3 from their position in the periodic table, which properties would you expect the elements vanadium, chromium and cobalt to have? 1 variable oxidation states 2 coloured compounds 3 high melting points a 1,2 and 3 b 1 and 2 only c 1 and 3 only d 2 and 3 only 4 the diagram shows part of the periodic table. which two letters represent elements that can react together to form covalent compounds? a w and x b w and y c x and y d y and z

Explanation:

Step1: Analyze question 1

Moving across a period from Group I to Group VII, non - metallic character increases, which means ability to form anions increases. Metallic character decreases, number of electron shells is the same across a period, and reactivity with water generally decreases for metals across a period.

Step2: Analyze question 2

In metals, the melting point is related to the strength of the metallic bond. The metallic bond is the attraction between positive ions and the 'sea of electrons'. Lithium has a stronger metallic bond due to smaller ion size and stronger attraction between positive ions and the 'sea of electrons' compared to sodium.

Step3: Analyze question 3

Vanadium, chromium and cobalt are transition metals. Transition metals have variable oxidation states, form coloured compounds and have high melting points due to strong metallic bonding.

Step4: Analyze question 4

Covalent compounds are formed between non - metals. Y and Z are non - metals and can react to form covalent compounds.

Answer:

1. A. ability to form anions
2. D. The attraction between the positive ions and the 'sea of electrons' is stronger in lithium than in sodium.
3. A. 1, 2 and 3
4. D. Y and Z