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