Atoms and the Periodic Table Flashcards
What are elements?
Elements are a pure substance meaning that only one type of atom exists in it.
What do elements usually refer to?
Elements usually refer to more than one atom
What are atoms comprised of?
Electrons, protons and neutrons
Location of electrons, protons and neutrons
Electrons are outside the nucleus and protons and neutrons are situated inside the nucleus.
What are the charges of protons, neutrons and electrons?
Electrons are negative, protons are positive and neutrons are neutral.
Provide some examples of changes in atoms that have had their protons added or subtracted.
Hydrogen has 1 proton and is an explosive gas. Helium has 2 protons and is an inert gas. Lithium has 3 protons and it’s a solid metal that fizzes in water.
Oxygen has 8 protons and Fluorine has 9 protons. The latter option kills you and eats your corpse while oxygen helps us live.
Where do element symbols originate from?
The latin name of the elements
Purpose of periodic table
To organise the elements
Hydrogen element symbol
Hydrogen (H)
Oxygen element symbol
Oxygen (O)
Carbon element symbol
Carbon (C)
Magnesium element symbol
Magnesium (Mg)
Aluminium element symbol
Aluminium (Al)
Iron element symbol
Iron (Fe)
Lead element symbol
Lead (Pb)
Gold element symbol
Gold (Au)
Chlorine element symbol
Chlorine (Cl)
Sodium element symbol
Sodium (Na)
Who published the periodic table?
Dmitri Mendeleev
When was the periodic table published?
In 1869
Why are there two separate rows at the bottom of the periodic table?
They are placed at the bottom to prevent making the periodic table too large
Name of the top separate row
Lanthanides
Name of bottom separate row
Actinides
Why is the periodic table shaped like it is?
The periodic table is shape is dictated on element reactivity.
What are the horizontal rows called?
Horizontal rows are named periods
What are the vertical columns called?
Vertical columns are arranged as groups
Define families
The bunches of elements with similar properties, usually they’re in the same group, but not always.
What are the four main types of classifications in the periodic table?
Metal, metalloids, transition metals and non-metals
Name of Group 1
Alkali metals
Characteristics of Alkali metals
They all react with water to give off hydrogen and heat and they are all metals
Percentage of metals in periodic table
80%
Percentage of non-metals in periodic table
15%
Percentage of metalloids in periodic table
5%
What happens as you proceed further down the group 1 elements?
The lower down the group you go, the more violent the reaction.
What elements separate the metals and majority of non-metals
Boron (B), Silicon (Si) , Germanium (Ge), Arsenic (As), Antimony (Sb), Tellurium (Te) and Polonium (Po)
Name of non-metal not separated by B, Si, Ge, As, Sb, Te and Po
Hydrogen
Element name B
Boron
Element name Si
Silicon
Element name Ge
Germanium
Element name As
Arsenic
Element name Sb
Antimony
Element name Te
Tellurium
Element name Po
Polonium
Name of Group 17
Group 17 are the Halogens.
Characteristics of Halogens
These non-metals are gases, they are all toxic (poisonous) and they all react with pretty much everything
Name of Group 18
Noble Gases
Characteristics of Noble Gases
These elements are all gases and they are also all inert
Use of Noble Gases
They are used in fluorescent lights
How to calculate atomic number
Atomic number = number of protons in the nucleus
How to calculate atomic mass
Atomic mass = number of protons + number of neutrons.
Why don’t we add electrons to the atomic mass equation?
We pretend electrons have no mass as their mass is 1/1840 of a proton.
What type of atomic mass includes decimals?
Average atomic mass includes decimals
What are isotopes
Isotopes are versions of an atom with different numbers of neutrons
How does the rarity of an isotope affect the atomic mass?
The atomic mass is based on how common each isotope is.
Is the atomic mass an average number?
Yes
How do we calculate the most common number of neutrons?
We round the atomic mass to the nearest whole number and use that for most calculations, to work out the ‘most common’ number of neutrons
What increases as you travel up a group or towards the right of a period?
Ionization energy, electronegativity and electron affinity increases as you travel to the right or the top of the periodic table.
What decreases as you travel up a group or towards the right of a period?
Atomic radius
What increases as you travel diagonally to the bottom left?
Metallic character
What decreases as you travel diagonally to the bottom left?
Non-metallic character
Is the number of electrons equal to the number of protons in a normal atom?
Yes
Why is the number of electrons equal to the number of protons in a normal atom?
Because electrons are negative and protons are positive, and the number of – must equal the number of + making it electrically neutral.
What are electron orbit paths called?
Electron shells
From where are electron shells numbered?
Inside out
Does each shell share the same maximum capacity?
No
If one shell is full of electrons, does the flow of electrons stop?
No, once one shell is full, the next electrons start filling up the next outer shell.
Define valence electrons
Outer electrons
Define valence shell
Outer shell
How do atoms interact with each other?
The only way atoms interact with others is through their electrons.
Which shell can interact with other atoms?
The outer shell of electrons (whichever one that is on a particular atom) is the only one that can interact with other atoms.
What goal do atoms want to achieve?
Elements ‘want’ to achieve noble gas configuration
Why do they want to achieve this goal?
Atoms with a ‘full’ outer shell don’t gain or lose electrons . They do not react with other elements, hence the unreactive ‘noble’ gases.
What makes elements so reactive?
An element with only 1 outer (valence) electron can easily lose this electron to another element (through a chemical reaction). It is this ‘ease of reaction’ that makes these elements so reactive.
What makes elements highly reactive
An element with 7 outer (valence) electrons ‘accepts’ electrons easily – in fact, they ‘rip’ electrons off atoms around them (through a chemical reaction). This aggressive attraction of electrons makes them highly reactive.
How many valence electrons do transition metals have?
2
Why do transition metals have unique properties
They have unique properties due to an orbital sub shell that is close to the valence or outer shell level.
How do the vertical (up/down) trends relate to the size of an atom?
When you travel downwards, the element has more electron shells meaning that the atom is larger than the element above it and smaller than the element below it.
How does the distance away from the nucleus affect electrons?
If an electron is further away from the nucleus, it feels the ‘pull’ of the positive protons in the nucleus less. Therefore, it is more loosely held to the atom. The further away the valence shell, the easier an element loses electrons. When the electron is closer to the nucleus the opposite occurs.
How does the reactivity of elements affect the simplicity to attract electrons?
The more reactive an element is, the easier it is to attract electrons while the opposite occurs when an element is more unreactive.
How are the periods numbered in the periodic table
They are numbered 1-7
How are the groups numbered in the periodic table
They are numbered 1-18
Number of elements that separate metals and non-metals
7
Define atom
The smallest particle of an element that has all of the chemical properties of that element.
Define Geiger counter
An instrument used for detecting and measuring radiation. Also known as a Geiger–Muller counter.
Define half-life
The time taken for half of the radioactive atoms in a sample to decay
Define matter
Physical substances made of atoms. It has weight and takes up space.
Define scientific model
A scientific model is a simplified representation or approximation containing the basic and most important parts of a real system, used to show how the real system works or can be changed.
Define nuclear radiation
Energy or particles that are released from the nucleus of a radioactive substance.
Define periodic table
A table of the chemical elements arranged in order of atomic number, usually in rows, so that elements with similar atomic structure (and hence similar chemical
properties) appear in vertical columns.
Define radioactive
A substance containing unstable atoms, which can spontaneously decay (break down) and emit nuclear radiation, either alpha or beta particles or gamma rays.
Define radioisotope
An isotope of an element that is unstable (and thus radioactive).
How many elements did Dmitri include when he first published the periodic table?
64
Name of group 2
Alkaline Earth Metals
Why is it called Alkaline Earth Metals?
Named after their oxides, the alkaline earths. These oxides are basic (alkaline) when combined with water.
Why is it called Alkali Metals?
The alkali metals are so named because when they react with water they form alkalies.
Why is it called Halogens?
Because they all produce sodium salts of similar properties
Why is it called Noble Gases?
They are called noble gases because they are so majestic that, in general, they don’t react with anything.
How to calculate number of neutrons?
Number of Neutrons = Mass number - Atomic number
Location of transition metals
Between Group 3-12
