Questions Flashcards
reaction of sodium with water symbol equation
2Na + 2H₂O —> 2NaOH + H₂
reaction of sodium with water word equation
sodium + water —> sodium hydroxide + hydrogen
properties of metals
-good conductors
-malleable
-ductile
-lustrous
-generally hard
-usually high density
-generally high melting and boiling points
-sonorous
-some of them corrode
-vary in reactivity
-tend to form cations
properties of nonmetals
-poor conductors, some exceptions
-usually good insulators
-brittle, not malleable/ductile
-lack lustre
-not sonorous
-vary in hardness
-usually low density
-generally low melting and boiling points, some exceptions like carbon
-vary in reactivity
-tend to form anions
what do u call an element which has properties of both metals and nonmetals
metalloids (or semimetals). examples include silicon and germanium.
describe newland’s periodic table
-arranged elements in order of their increasing atomic weight
-similar properties seemed to reappear every eighth elements, like musical octaves
-his system worked well for lighter elements but broke down as the atomic weights increased.
-elements which weren’t at all similar to each other were grouped together, as he wanted to maintain the octave pattern. this made his table inaccurate and unconvincing to the scientific community.
describe mendeleev’s periodic table
-mendeleev also arranged elements by increasing atomic weight, but prioritised placing elements with similar properties in the same groups.
-mendeleev left gaps in his periodic table for undiscovered elements. he also predicted the properties of these missing elements based on the properties of their neighbouring elements.
why was mendeleev’s periodic table more acceptable than newland’s?
-the successful prediction of undiscovered elements proved that mendeleev’s table was more accurate than newland’s
-its organisation was more accurate because the elements were grouped with elements that were similar to each other
what does the atomic number tell you
how many protons/electrons are in the element/atom.
what does the mass number tell you
how many neutrons+protons are in the element/atom.
what does the group number tell you
how many electrons are on the outer shell
what does the period number tell you
how many shells there are in the electron configuration
which elements have multiple types of ions
transition metals (typically)
what colour do you see when iodine gets displaced
dark brown/purple-brown
what is chlorine used for
removing bacteria and viruses from swimming pools
what are transition metals used for
they are usually used as catalysts
describe halogens group 7
-the colour of the elements gets darker as you go down the group
-the melting and boiling point increases as you go down the group, as the intermolecular forces are bigger, so they’re stronger.
-all elements in group 7 are diatomic, which means they consist of 2 atoms. ONLY when they’re in element form, not compound form.
-less reactive as you go down the group, as it’s harder for them to gain an electron to form an ion.
describe alkali metals group 1
-quite soft, can be cut with a knife
-low melting points for metals
-as you go down the group, the reactivity increases
-malleable
-high thermal + electrical conductivity
-as you go down the group it gets easier to lose the outer electron as the electron is farther away from the nucleus(because there’s more shells) which has a positive charge and therefore they don’t attract as much.
describe transition metals group 3
-electrical conductors
-hard
-high melting/boiling point
-dense
-some react with oxygen in the presence of water to rust, like iron
-form coloured compounds
-can be used as catalysts
-can form ions with different charges
-some are very unreactive (silver and gold)
-react with halogens
-react with water
what is electron shielding
the further down the group you go, the more electrons there are. therefore, they repel each other and make it easier to remove the electrons/harder to gain an electron. The more electrons, the larger the repulsive force.
group 0 description
group 0 contains non-metal elements. the elements in group 0 are called noble gases. they are inert (very unreactive) because they already have a full outer shell and therefore don’t need to gain or lose any electrons in order to become an ion.
a chemical property is that they have full outer shells. a physical property is that as you go down the group, the boiling point increases because the atoms get larger, so they have stronger intermolecular forces.
