Periodic Table Flashcards
how did Mendeleev arrange the elements in his periodic table? (2)
- in order of increasing relative atomic mass.
- put elements with similar properties into groups
what changes to the order did Mendeleev make to make his classifications work? (2)
- left gaps for yet to be discovered elements
- switched the order of a few elements to keep the groups consistent
how are elements arranged in a modern periodic table?
-according to their atomic number
what are rows and columns also known as?
rows = periods columns = groups
what do elements of the same group have?
similar chemical properties
how could Mendeleev predict the properties of these undiscovered elements?
-by looking at the chemical and physical properties of the elements next to a gap
what is an electronic configuration?
way in which electrons are arranged in an atom.
how many electrons can be held in each shell for elements with AN between 1-20?
- 2 in the first
- 8 in the subsequent and so on
how can the electron configuration be predicted?
-atomic number
what does the number or numbers of shells in the electronic configuration relate to?
period number
what does the number or numbers of electrons in the outermost shell relate to?
group number
what does the total number or numbers of electrons in all shells relate to?
atomic number
what does the electronic configurations of atoms help explain ? (2)
- properties of elements
- structure of the periodic table.
why do elements in the same group have similar chemical properties?
- when atoms collide and react, it is the outer electrons that meet and interact
- therefore elements in the same group have similar chemical properties because they have the same number of electrons in their outer shell.
why are some atoms more predisposed to becoming ions?
Groups 1, 2, 6 and 7 form ions very easily. This is because they only need to gain or lose a small number of electrons, and so less energy is required.
Those in groups 3, 4 and 5 do not form ions very easily, because they need to gain or lose a larger number of electrons, and therefore more energy is required.
