The number of valence electrons for elements in Group 16 is _____.
6
According to Dalton's postulates, how do atoms relate to elements?
None of the above
The same atom may be part of 2 or more elements
All elements are composed of atom & all atoms are identical
Atoms of one element differ from atoms of other element
By knowing the number of protons a neutral atom has, you should be able to determine
the number of electrons in the neutral atom
the number of neutrons in the neutral atom
the name of the atom
two of these
How are ions formed?
By adding or taking away an electron from an atom
Isotopes of the same element can differ in
mass number/number of neutrons
How many protons, electrons, and neutrons does a neutral atom with an atomic number of 50 and a mass number of 120 contain?
50 protons, 50 electrons, 70 neutrons
How many neutrons are in the nucleus of iodine-131?
78
What element is represented by the Bohr model?
Lithium
What particles form the nucleus of an atom?
protons and neutrons
Which one of the following statements about atomic structure is false?
An atom is mostly empty space.
Proton & neutron number is always the same in a neutral atom
Almost all of the mass of the atom is in the nucleus
Protons and neutrons in the nucleus are very tightly packed
What does the number 84 in Krypton-84 represent?
the mass number
T or F. Oxygen-18 and Fluorine-19 have the same number of neutrons.
True
Which scientist discovered the electron?
Thomson
How many valence electrons does this element have?
3
How many neutrons does an atom with an atomic mass of 9 and an atomic number of 5 contain?
4
An element has an atomic number of 80. How many protons and electrons are in a neutral atom of this element?
80 protons and 80 electrons