Chapter 1 Flashcards
Elements and the periodic table
What is an atom?
The smallest piece of an element that retains the properties of that element.
Define atomic number.
The number of protons present in the nucleus of an atom.
What is a chemical property?
The behaviour of an element or substance when it reacts with another element or substance.
What is a compound?
A substance formed from two or more different types of atoms in a fixed ratio.
What does diatomic mean?
An element that consists of two atoms; the prefix di means ‘two’.
What is an electron?
A negatively charged subatomic particle that moves around the nucleus of an atom.
What is an ion?
A positively or negatively charged atom that has either lost or gained electron(s).
Define isotope.
An atom of the same element with the same number of protons but a different number of neutrons.
What is mass number?
The total number of protons and neutrons present in the nucleus of an atom.
What is a neutron?
An uncharged subatomic particle present within the nucleus of an atom.
What is a proton?
A positively charged subatomic particle present within the nucleus of an atom.
What does relative atomic mass represent?
The average of the relative masses of all atoms for an element based on the isotopes and their natural percentage abundances.
True or False: Elements contain only one type of atom.
True.
Fill in the blank: An element made up of single atoms of the same type is _______.
monoatomic.
Fill in the blank: The mass number is calculated using the formula: mass number = number of protons + _______.
number of neutrons.
What is the charge and location of protons?
Positive charge, located in the nucleus.
What is the charge and location of electrons?
Negative charge, located in shells around the nucleus.
What is the charge and location of neutrons?
No charge, located in the nucleus.
What are the two types of elements based on atomic composition?
- Monoatomic
- Diatomic
What is the significance of atomic notation?
It communicates the chemical symbol, atomic number, and mass number of an element.
How do you determine the number of neutrons in an atom?
Number of neutrons = mass number - atomic number.
What happens to an atom when it gains or loses electrons?
It becomes an ion with an overall electric charge.
What is the atomic notation for magnesium?
24Mg with atomic number 12.
What is the difference between mass number and relative atomic mass?
Mass number is a whole number representing protons + neutrons; relative atomic mass is an average that may be fractional.
How do you represent the charge of an ion in atomic notation?
Using a superscript positive or negative charge after the chemical symbol.
What is the role of subatomic particles?
They determine the characteristics of each type of atom.
Identify the three main subatomic particles.
- Protons
- Neutrons
- Electrons
What is the number of electrons in a neutral atom?
It is equivalent to the atomic number of an element.
How do you determine the number of electrons in an ion with a positive charge (Mx+)?
Number of electrons = atomic number - x.
How do you determine the number of electrons in an ion with a negative charge (Xy−)?
Number of electrons = atomic number + y.
What is the charge of the phosphide ion?
3–.
How many electrons does the phosphide ion have?
18 electrons.
What is the significance of noble gases in relation to ions?
Ions will have the number of electrons equivalent to a noble gas (full outer shell of electrons).
What is the Aufbau principle?
It describes the order in which electrons fill orbitals and shells.
What is the Bohr model of the atom?
A model that depicts electrons in specific levels or ‘shells’ orbiting the nucleus.
What is an emission spectrum?
The electromagnetic radiation emitted by a source, such as atoms.
What happens to electrons when they become excited?
They gain energy and move to a higher energy level.
What is the ground state of an electron?
The lowest possible energy state of an electron, closest to the nucleus.
What is a valence shell?
The outermost shell of an atom.
What is a valence electron?
An electron found in the outermost shell of an atom.
What is the maximum number of electrons in a shell according to the formula 2n²?
Depends on the shell number (n). For example, shell 1 has 2, shell 2 has 8.
What is the maximum number of electrons in the outer shell?
The outer shell can never contain more than eight electrons.
Fill in the blank: The outermost shell is called the ______.
valence shell.
How do you write electron configurations according to the Bohr model?
In the form: number of electrons in first shell, number in second shell, etc.
What is the electron configuration for oxygen (atomic number 8)?
2,6.
How do you determine the electron configuration for an ion?
It should have the same electron configuration as that of noble gases.
What model did Erwin Schrödinger develop?
The Schrödinger model, or quantum mechanics model.
What does the Schrödinger model treat electrons as?
Electrons are treated as waves with wave-like properties.
What are orbitals?
Regions of space where electrons are most likely to be found.
What are the labels for subshells?
s, p, d, and f.
What is a subshell?
A region within a shell composed of certain numbers of orbitals.
What are the types of subshells?
- s
- p
- d
- f
What is an orbital?
A three-dimensional description of the most likely location for an electron within a region of an atom.
How many electrons can each orbital hold?
A maximum of two electrons.
According to the Bohr model, how do electrons occupy energy levels?
Electrons occupy the lowest possible energy levels (or subshells) first.
What is the first step to determine electron configurations using the subshell model?
Know how to read the periodic table and the location of different subshells.
What is the maximum number of electrons that can be held in the first shell?
2
What is the maximum number of electrons that can be held in the second shell?
8
What is the maximum number of electrons that can be held in the third shell?
18
What is the maximum number of electrons that can be held in the fourth shell?
32
What does the superscript in the electron configuration represent?
The number of electrons in the subshell.
What does the coefficient in the electron configuration denote?
The shell number (n).
What rule describes the order of filling subshells with electrons?
Aufbau’s principle.
What does Hund’s rule state?
Every orbital in a subshell contains only one electron before any orbital is fully occupied with two electrons.
What is the electron configuration of carbon?
1s22s22p2
What are the exceptions to the filling order of subshells in transition metals?
- Chromium (Cr): 1s22s22p63s23p64s13d5
- Copper (Cu): 1s22s22p63s23p64s13d10
Fill in the blank: The noble gas shorthand notation for aluminium is _______.
[Ne] 3s23p1
What happens to the electron configuration of an atom when it forms a positively charged ion?
It resembles that of a full outer shell.
How do you check the correctness of an electron configuration?
Add together the superscript numbers to equal the number of electrons present.
What is the core charge?
A concept that helps explain the attraction between the nucleus and the electrons.
What is electronegativity?
A measure of the tendency of an atom to attract a bonding pair of electrons.
Who is credited with the development of the periodic table?
Dmitri Mendeleev
Mendeleev’s work built upon earlier contributions from scientists like Antoine Lavoisier, Johann Döbereiner, and John Newlands.
What method did Mendeleev use to organize the elements?
He used cards with chemical symbols, atomic weights, and properties
He spent three days and nights arranging them until he had a breakthrough in his sleep.
What significant pattern did Mendeleev notice in the properties of elements?
Repetition of properties every eight elements
This observation was crucial for forming the basis of his periodic table.
What did Mendeleev do about undiscovered elements?
He left spaces in the periodic table for them and predicted their properties
Elements like gallium, scandium, and germanium confirmed his predictions.
When was the modern periodic table organized by atomic number instead of atomic mass?
In 1913 by Henry Moseley
This change improved the accuracy of the periodic table.
What is the periodic table primarily organized by?
Increasing atomic number and variations in chemical properties
This organization reflects the repeating patterns of electron configurations.
What are the vertical columns in the periodic table called?
Groups
There are 18 groups numbered 1-18.
What do elements in the same group have in common?
Similar electron configurations and chemical properties
For example, all group 17 elements share similar properties.
What are the horizontal rows in the periodic table called?
Periods
There are seven periods numbered 1-7.
What does the period of an element indicate?
The number of occupied electron shells in the element’s atoms
Define ‘core charge’.
The electrostatic force of attraction between valence electrons and the nucleus
Calculated by subtracting the number of non-valence electrons from the number of protons.
What happens to core charge as you move left to right across a period?
Core charge increases
This results in a greater attraction between valence electrons and the nucleus.
How does atomic radius change across a period?
Atomic radius decreases
As core charge increases, valence electrons are drawn closer to the nucleus.
What is the atomic radius?
A measure of the size of an atom from the nucleus to its valence shell
What is electronegativity?
The ability of an atom to attract electrons towards itself
Influenced by core charge and atomic radius.
True or False: An element further to the right in the periodic table but in the same period will have a greater core charge.
True
True or False: An element further towards the top of a group will have a larger atomic radius.
False
What is the trend for electronegativity as you move down a group?
Electronegativity decreases
Due to increased atomic radius and weaker attraction of valence electrons to the nucleus.
List the common groups and their properties.
- Group 1: Alkali metals - Soft, very reactive with water
- Group 2: Alkaline earth metals - Good conductors, relatively low density
- Group 17: Halogens - Coloured gases, odorous
- Group 18: Noble gases - Unreactive
What is electronegativity?
The ability of an atom to attract shared electrons to itself.
How does electronegativity change across a period?
Electronegativity increases across a period.
How does electronegativity change down a group?
Electronegativity decreases down a group.
What is the trend for first ionisation energy across a period?
First ionisation energy generally increases as you go across a period.
What is the trend for first ionisation energy down a group?
First ionisation energy generally decreases as you start a new shell.
What is first ionisation energy?
The energy required to remove the outermost electron from a gaseous atom.
What are the general properties of metals referred to as metallic character?
Ability to conduct electricity and heat, relatively high melting and boiling points, and few valence electrons.
What happens to metallic character as you move across a period?
Metallic character decreases.
Fill in the blank: The atomic radius is the measure of the size of an atom from the centre of the nucleus to its _______.
valence shell.
What defines a critical element?
A chemical element essential to the economic or national security of a nation and vulnerable to disruption of supply.
What is the boiling point?
The temperature at which the vapour pressure above the liquid equals the pressure exerted by the surroundings on the liquid.
What is the melting point?
The temperature at which a solid melts.
True or False: Non-metals tend to want to lose electrons.
False.
What is the trend for non-metallic character across a period?
Non-metallic character increases.
What happens to atomic radius as you go down a group?
Atomic radius increases.
What is the core charge?
The effective nuclear charge experienced by the valence electrons.
Explain the relationship between electronegativity and first ionisation energy.
Higher electronegativity usually correlates with higher first ionisation energy.
Using the example: Which element has a higher electronegativity, oxygen or nitrogen?
Oxygen.
Using the example: Which element has a higher first ionisation energy, arsenic or antimony?
Arsenic.
What role do critical elements play in modern technology?
They are essential for the manufacture of products and technologies.
What is the significance of recycling critical elements?
To recover elements before they are depleted.
What happens to the reactivity of metals as their metallic character increases?
The more easily a metal loses electrons, the more reactive it is.
What does the trend for ionisation energy indicate about noble gases?
Noble gases have higher first ionisation energies due to full valence shells.
What is the effect of atomic radius on ionisation energy?
A larger atomic radius generally results in lower ionisation energy.
Fill in the blank: The stronger the electrostatic force of attraction between valence electrons and the nucleus, the _______ the ionisation energy.
greater.
What are technology-critical elements?
Elements essential to the economic or national security of a nation that are vulnerable to supply disruption
Examples include elements vital in manufacturing or technology spread, whose absence would harm economic or defense capabilities.
What is Helium classified as?
A non-metal, colourless, odourless, non-toxic noble gas found in group 18
It has the lowest boiling and melting point of all elements.
What is the melting point of Helium?
–268°C (5.2 K)
Helium can remain a liquid at absolute zero (0 K).
How is Helium primarily sourced?
As a by-product of natural gas extraction and from the radioactive decay of uranium and thorium
Some Helium is trapped in Earth’s mantle.
What is the location of the world’s largest supply of Helium?
National Helium Reserve in Amarillo, Texas
It holds approximately 670 million cubic meters as of 2019.
Why is Helium classified as a critical element despite its abundance?
It escapes Earth’s atmosphere constantly and its supply is diminishing
The deterioration rate is estimated at approximately 0.5% per year.
What are the main uses of Helium?
- Cryogenics
- Semiconductor chip manufacture
- Aerospace industry
- Optical fiber manufacture
- Nuclear power generation
Helium is crucial in cooling superconducting magnets in MRI and NMR devices.
What environmental issue is associated with Helium extraction?
Carbon dioxide production when sourced from natural gas
This has greater impacts on the environment.
What is Phosphorus essential for?
All life, as it is a key element in DNA, cell membranes, bones, and teeth
It is also a key ingredient in many fertilizers.
Where is the majority of the world’s phosphate rock mined?
Morocco
Approximately 70% of the world’s phosphate rock mines are located there.
What is eutrophication?
Dense growth of plant life due to high nutrient concentrations in water
Commonly caused by agricultural runoff and wastewater.
What is the estimated timeline for phosphorus resource depletion?
Around 2080
This is due to increased global demand for food production.
What are rare-earth elements?
A group of 17 elements including lanthanides, yttrium, and scandium
They are strong reducing agents and often found in low concentrations.
What are the classifications of rare-earth elements?
Light elements (La to Sm) and heavy elements (Eu to Lu)
Heavy elements are less common and more expensive.
What significant change occurred in rare-earth element production in the mid-1980s?
China began selling these elements at very low prices
This forced mining in the USA to stop due to lack of profitability.
What are some applications of rare-earth elements?
- Smart phones
- Digital cameras
- LED televisions
- Computer hard disks and monitors
They are also used in electric and hybrid vehicles.
What are post-transition metals?
Elements found between transition metals and metalloids
They have distinct physical and chemical properties.
What is the primary use of Aluminium?
Utensils, electronics, and soldering
It is the most abundant post-transition metal.
What is the process of smelting?
Heating and melting an ore to extract a metal
Slag is the by-product of this process.
What is the significance of tin in history?
Used since the Bronze Age (around 3000 BCE)
It is extracted from the ore cassiterite (SnO2).
What is the process used to extract tin from ores?
Smelting
Smelting involves heating tin concentrate with carbon to form crude tin and slag.
What are the two common refining processes for tin before market sale?
- Heat treatment
- Electrolysis
Heat treatment is more common due to its lower cost and acceptable purity levels.
What is the recycling efficiency of tin?
High quality recycling, especially from electronic products
Tin is used in solder, cans, and batteries, making its recycling economically valuable.
Which metal is 100% recyclable without losing properties?
Lead
Lead is mainly recycled from lead-acid batteries, with 90% of scrap lead in Australia coming from this source.
What percentage less energy does recycling lead use compared to obtaining primary lead?
35-40% less energy
This efficiency makes lead recycling economically advantageous.
What is the approximate percentage of all aluminium ever produced that is still in use today?
75%
Aluminium has a high recycling rate, contributing to its sustainability.
What makes bismuth difficult to recycle?
Used in pharmaceuticals, chemicals, and paints
These products are often consumed or dissipated after use, complicating recycling efforts.
Which metalloids are currently considered critical?
- Germanium
- Arsenic
- Tellurium
These elements have significant industrial applications and are often recovered as by-products.
What are the physical properties of metalloids?
- Lustrous
- Solid
- Brittle
- Conduct electricity
Metalloids have properties that are intermediate between metals and non-metals.
What are the chemical properties of metalloids?
- Easily form anions (except boron)
- Multiple oxidation states
- Electronegativities between metals and non-metals
These properties dictate their reactivity in chemical reactions.
What is an example of a metalloid used in fuel ignition?
Boron
Boron forms covalent bonds and has applications in medical antiseptics.
What is the typical recycling efficiency of germanium?
76%
This efficiency was estimated in 2000, primarily in optical fibre applications.
What is a significant global initiative regarding recycling by Apple?
To create smartphones from only recycled material
This commitment reflects a shift towards sustainable manufacturing practices.
What are two key benefits of recycling?
- Conserving natural resources
- Reducing waste in landfills
Recycling also helps stimulate the development of greener technologies.
True or False: The circular economy focuses on optimising the reuse of materials.
True
The circular economy contrasts with the linear economy, which is based on a ‘take-make-dispose’ model.
What is a potential negative environmental impact of mining?
- Loss of landscape
- Pollution from extraction processes
- Noise pollution
These impacts can have significant consequences for local ecosystems.
What is the main focus of a circular economy?
Continuous cycle of resource use and reuse
This approach aims to minimise waste and make the most of resources.
