Isotopes have the same mass number but different atomic number.
True?
False?
False
300
How did Mendeleev arranged his periodic table?
by increasing atomic mass
300
Li is a:
a)Alkali metal
b) transition metal
c) alkaline earth metal
a) Alkali metal (1A)
400
what was Democritus contribution to the discovery of the atom?
was a philosopher (Not a scientist) He claimed that matter was made of small, hard particles that he called “atomos”
400
Anode is negatively charged.
true?
false?
False
400
Are the following isotopes?
Carbon-12 and Carbon-13
yes they are isotops
400
The element with almost a 69 mass number is ......
Ga (Gallium)
400
What is a valance electron?
electrons in the highest occupied energy level.
500
A sample of copper with a mass of 60g contains (7.02x10) atoms. Calculate the mass of a single copper atom.
0.85
500
Rutherford experiment is called..............
Gold-foil experiment
500
Isotope 1 has an Atomic mass of 10.012 and Percent 19.91%.
Isotope 2 has an Atomic mass of 11.009 and Percent 80.09%.
What is the atomic mass for the element?
10.81
500
What did the (?) mark in Mendeleev's periodic table meant?
These elements weren't discovered yet
500
If an element is in group 2 and period 5.
What is its energy level and number of valance electrons?