(a) Define (i) atomic number, (ii) relative atomic mass - Leaving Cert Chemistry - Question 5 - 2006
Question 5
(a) Define (i) atomic number, (ii) relative atomic mass.
(b) The two best-known isotopes of carbon are carbon-12 and carbon-14.
(i) What term is used in chemistry ... show full transcript
Worked Solution & Example Answer:(a) Define (i) atomic number, (ii) relative atomic mass - Leaving Cert Chemistry - Question 5 - 2006
Step 1
Define (i) atomic number
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The atomic number is defined as the number of protons in the nucleus of an atom. This unique identifier allows elements to be arranged in the periodic table.
Step 2
Define (ii) relative atomic mass
99%
104 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The relative atomic mass is the average mass of the atoms of an element relative to 1/12th of the mass of the carbon isotope C-12. It reflects the weighted average of all the isotopes of that element.
Step 3
(b)(i) What term is used in chemistry for the numbers (e.g. 12 and 14 in the case of carbon above) used to identify particular isotopes of an element?
96%
101 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The term used is 'mass number'. It refers to the total number of protons and neutrons in an atomic nucleus.
Step 4
(b)(ii) Name the subatomic particle that is responsible for the difference between carbon-12 and carbon-14. How many of these particles are found in an atom of carbon-14?
98%
120 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The subatomic particle responsible for the difference is the neutron. Carbon-12 has 6 neutrons, while carbon-14 has 8 neutrons, leading to the difference in mass number.
Step 5
(b)(iii) Explain what a β-particle is. Give one use of carbon-14.
97%
117 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
A β-particle is a high-energy, high-speed electron or positron emitted during radioactive decay, specifically during the process of beta decay. One common use of carbon-14 is in radiocarbon dating, a method used to determine the age of ancient organic materials.
Step 6
Define electronegativity.
97%
121 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Electronegativity is defined as the measure of the hold (pulling power, relative attraction) of an atom of an element for a pair of electrons in a covalent bond or for a shared pair of electrons.
Step 7
(c)(i) carbon and sulfur
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Covalent bond, as both carbon and sulfur have similar electronegativity values, allowing them to share electrons fairly equally.
Step 8
(c)(ii) potassium and fluorine
99%
104 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Ionic bond, as potassium has a low electronegativity and fluorine has a high electronegativity, leading to the transfer of electrons from potassium to fluorine.
Step 9
(c)(iii) hydrogen and chlorine
96%
101 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Polar covalent bond, since hydrogen and chlorine have different electronegativities, leading to unequal sharing of the bond electrons.
Join the Leaving Cert students using SimpleStudy...
