science C2 Flashcards
list the significant models for ordering the elements (john, law of octaves, aranged, atomic mass, every 8th, similar, 1864 – dmitri, catgorised, according, atomic mass, gaps, at time, 1869).
- John Newland proposed his ‘law of octaves’ where he arranged the elements in order of their atomic mass. Newland noticed that every 8th element had similar chemical properties, 1864
- Dmitri Mendeleev categorised the elements arranged according to atomic mass, left gaps in his table to place elements not known at the time, 1869
define a group and a period in the periodic table,(rows, columns)
Periods are horizontal rows (across) the periodic table, while groups are vertical columns (down) the table.
state the trend in reactivity in group 1(increases, group,atoms, larger, outer, further, nucleus)
increases as you go down the group because the atoms become larger and the outer electron becomes further from the nucleus.
state the trend in reactivity in group 7(decrease, mass , increase, electron shells, atoms, larger, down the group)
The reactivity of the halogens decreases because the atomic mass of the halogens increases and they increase in electron shells so the atoms are larger as you go down the group.
list the typical properties of transition metals(conductors,heat,bent,density)
- they are good conductors. of heat and electricity.
- they can be hammered or bent into shape easily.
- they have high densities.
state how the elements are ordered in the periodic table(atomic number, rows, columns, elements, same group, chemical preoperties)
in order of increasing atomic number. The horizontal rows are called periods and the vertical columns are called groups. Elements in the same group have similar chemical properties.
what is the state of reactivity in a noble gas
- have complete outer shells, so they have no tendency to lose, gain, or share electrons.
- This is why the noble gases are inert and do not take part in chemical reactions.
how is the electronic structure linked to the periodic table
the number of circles in the electronic configuration of an element is represented in the periodic table as the period number that element is situated in.
what are the main properties of halogens
- low melting and boiling points,
- They are highly reactive, especially with alkali metals and alkaline earths- sparingly soluble in water
how does the electronic structure affect the reactivity of elements
The further away the outermost negative electron is from the positive nucleus, the weaker the force of electrostatic attraction between the two is and the easier it is for the element to react as less energy is required to remove the electron
why are noble gases unreactive
The atoms of noble gases already have complete outer shells, so they have no tendency to lose, gain, or share electrons. This is why the noble gases are inert and do not take part in chemical reactions.
how is the structure of metals and non metals are different
The electrons in nonmetals are localized in covalent bonds, whereas in a metal, there is delocalization of the electrons throughout the solid
what happens in a halogen displacement reaction
more reactive halogen can displace a less reactive halogen from a solution of its salt. All these reactions occur in solution and all the salts when dissolved in water are colourless.
why do group 1 and 7 act similarily
they all have one electron in their outer shell.
how does the electronic structure affect reactivity of elements
The number of electrons in the outermost shell of a particular atom determines its reactivity, or tendency to form chemical bonds with other atoms
