1.1 Atomic structure Flashcards
What is meant by the term element?
an element consists of only one type of atom/cannot be broken down
into anything simpler by chemical means
What is meant by the term atomic number?
number of protons in an element
Explain what is meant by relative in the term relative atomic mass.
The relative atomic mass is the mass of the atom compared with that of the carbon-12 isotope, which has a mass of exactly 12, and it is the weighted mean of the mass numbers.
What is an isotope?
Isotopes are atoms which have the same number of protons (so they are atoms of the same element) but they have a different number of neutrons (so they have a different mass number).
What is the charge of a proton?
Positive
What is the charge of an electron?
Negative
What is the charge of a neutron?
No charge
What is the mass of a proton?
1 atomic mass unit
What is the mass of a neutron?
1 atomic mass unit
What is the mass of an electron?
1/1840
Where in the atom are protons located?
In the nucleus
Where in the atom are neutrons located?
In the nucleus
Where in the atom are electrons located?
In shells surrounding the nucleus
Describe the Plum pudding model of the atom.
JJ Thomson’s Plum Pudding Model of the atom considered it having negative electrons embedded in a continuous matrix of positive charge. The electrons like currants embedded in the positively charged cake matrix of the pudding.
Who discovered the neutron
James Chadwick
Describe Rutherford’s model of the atom.
Rutherford’s model compared the atom to the Solar system, where negatively charged electrons orbit a tiny, central and positively charged nucleus: like the Planets orbit the Sun.
Why are atoms chemically neutral?
They have equal numbers of positively charged protons and negatively charged electrons.
What is the definition of an ion?
An electrically charged particle formed when an atom gains or loses electrons.
What is a cation?
A positively charged ion formed when an atom loses an electron or electrons.
What is an anion?
A negatively charged ion formed when an atom gains an electron or electrons.
What is a molecule?
A particle made from two or more atoms covalently bonded.
What is meant by the mass number of an element?
The total number of protons and neutrons in the nucleus of an atom.
How many protons, electrons and neutrons are in the element Magnesium?
Protons = 12
Electrons = 12
Neutrons = 24 - 12 = 12
How many protons, electrons and neutrons are in the element Oxygen?
Protons = 8
Electrons = 8
Neutrons = 16 - 8 = 8
How many protons, electrons and neutrons are in the ion oxide?
Oxide ion has a charge of 2-
Protons = 8
Electrons = 8 + 2 = 10
Neutrons = 16 - 8 = 8
How many protons, electrons and neutrons are in the ion of aluminium?
aluminium ion has a charge of 3+
Protons = 13
Electrons = 13 - 3 = 10
Neutrons = 27 - 13 = 14
Name and give the charge of the ion that has an atomic number of 7, but has 10 electrons
Nitrogen with a 3- charge
Name and give the charge of the ion that has an atomic number of 11, but has 10 electrons
Sodium with a 1+ charge
What element has the electronic arrangement of 2,8,8,1?
Potassium
19 electrons = atomic number
What element has the electronic arrangement of 2,8?
Neon
10 electrons = atomic number
Which ion has the electronic arrangement of 2,8 with a charge of 2-?
Oxide ion
Which ion has the electronic arrangement of 2,8,8 with a charge of 2+?
Calcium ion
What is the typical size of an atom?
0.1 nanometers.
How much smaller is the radius of an nucleus compared to the radius of the atom?
ten thousand times smaller
1/10,000
Analysis of potassium showed it has three isotopes with the following mass numbers and abundances:
93.1% 39K, 0.012 %, 40K and 6.9 % are 41K.
Calculate the accurate relative atomic mass of potassium to three decimal places.
Ar of Potassium
= (39 x 93.1/100) + (40 x 0.012/100) + (41 x 6.9/100)
= 36.3090 + 0.0048 + 2.8290
= 39.1428
Ar of K = 39.143
