properties Flashcards
What is the mass number?
The total number of protons and neutrons
How does one calculate the number of neutrons using mass number and atomic number?
Subtract the atomic number from the mass number
What is an isotope? Do isotopes
of a certain element have the same
chemical properties?
Atoms of the same element (same proton number) that have a different number of neutrons.
They have the same chemical properties as they have the same electronic structure
What is the relative atomic mass?
The average mass value which takes the mass and abundance of isotopes of an element into account, on a scale where the mass of 12C is 12.
What are ions?
Ions are charged particles. They are formed when atoms lose electrons
(positive ions) or gain (negative ions) electrons.
What is formed when a metal reacts with a non-metal?
An ionic compound (made of positive and negative ions).
What is formed when a non-metal reacts with a non-metal?
A compound containing covalently bonded atoms.
- Atoms share electrons, as opposed to transferring electrons between each other (cf. ionic compounds).
Are elements in the same
group similar or different?
They may have similar chemical properties, as they have the same number of outer shell electrons.
Early periodic tables were
incomplete and elements were
placed in inappropriate groups if
what was to be followed?
The strict order of atomic weights, law of octaves, some groups had completely different properties
Mendeleev overcame some
problems with the table by doing
what? He also changed the order
of some elements based on what?
started organising the elements in increasing atomic weights
- switched order of elements, so they fit the pattern of other elements in the same group
- some elements hadn’t been discovered, and left gaps.
- He predicted the properties of the elements based off of his table
Elements that react to form
positive ions are…?
Metals
Elements that do not form
positive ions are…?
Non-metals
How do you calculate relative atomic mass?
(mass no. of Isotope 1 x percent abundance of isotope 1) + (mass no. of isotope 2 x percent abundance of isotope 2)
÷
100
How is the modern periodic table different from mendeleev’s table?
- elements are arranged in order of atomic number
- protons hadn’t been discovered when he made his, his was ordered in atomic weight, bad because some elements were in the wrong order bc of isotopes
- modern table has group 0, noble gases, weren’t discovered when he made his table.
what is the test for chlorine gas?
damp litmus paper turns white
