WAEC offline past questions - with all answers and explanations in one app - Download for free
WAEC Past Questions, Objective & Theory, Study 100% offline, Download app now - 24709

1988 WAEC Chemistry Theory (a) An element X is represented as \(^{40}_{20} X\) (i) How many electrons and how...

Chemistry
WAEC 1988

(a) An element X is represented as \(^{40}_{20} X\)

(i) How many electrons and how many neutrons are present in the atom of X?

(ii) Write the electronic configuration of the atom

(b) Chlorine, whose atomic number is 17, reacts with the element X to form a compound.

(i) What type of bond is formed between X and chlorine?

(ii) Explain how the bond between X and chlorine is formed

(iii) Write the formula of the compound formed and statelhree properties of the compound.

(c) Chlorine has two isotopes of mass numbers 35 and 37 respectively. Suggest the possible relative molar masses of a chlorine molecule.

(d) Calculate the mass of one atom of carbon, given that one mole of carbon weighs 12.0g. (L = 6.02 x 10\(^{23}\))

WAEC May/June 2024 - Practice for Objective & Theory - From 1988 till date, download app now - 99995
WAEC offline past questions - with all answers and explanations in one app - Download for free
WAEC Past Questions, Objective & Theory, Study 100% offline, Download app now - 24709
Explanation

(a)(i) 20 electrons and 20 neutrons

(ii) 1s\(_2\), 2s\(_2\), 2p\(_6\), 3s\(_2\), 3p\(_6\), 4s\(_2\)

 

(b)(i) Ionic bond

(ii) Element X has valency electrons of 2 which it completely lost to two chlorine atoms which has valency electrons of 7 respectively. By the above event, each of the atoms involved in the bond completes its outermost octet electronic structure of stability as the noble elements. They then come together as aggregates of ions of opposite charges.

(iii) XCl\(_2\) : It dissolves in water. It can conduct electricity. It has high boiling point

 

(c) The relative molar mass of chlorine is 35.5

 

(d) 6.02 x 10\(^{23}\) atoms

C = 12.0g

1 atom C = \(\frac{12.}{6.02}\) x 10\(^{-23}\)

= 2.0 x 10\(^{-23}\)g


Report an Error Ask A Question Download App
WAEC offline past questions - with all answers and explanations in one app - Download for free
WAEC May/June 2024 - Practice for Objective & Theory - From 1988 till date, download app now - 99995
WAEC Past Questions, Objective & Theory, Study 100% offline, Download app now - 24709

Contributions ({{ comment_count }})

Please wait...

{{ settings.no_comment_msg ? settings.no_comment_msg : 'There are no comments' }}

Quick Questions

Post your Contribution

Please don't post or ask to join a "Group" or "Whatsapp Group" as a comment. It will be deleted. To join or start a group, please click here

{{ quote.posted_by.display_name }}
{{ settings.form_textarea_description }}
 
WAEC May/June 2024 - Practice for Objective & Theory - From 1988 till date, download app now - 99995
WAEC Past Questions, Objective & Theory, Study 100% offline, Download app now - 24709
WAEC offline past questions - with all answers and explanations in one app - Download for free
WAEC Past Questions, Objective & Theory, Study 100% offline, Download app now - 24709
WAEC May/June 2024 - Practice for Objective & Theory - From 1988 till date, download app now - 99995
WAEC offline past questions - with all answers and explanations in one app - Download for free