The Nucleus of an Atom
Subatomic particle with positive charge
proton
The mass number of an atom is equal to the total number of its
protons and neutrons
What are the two subatomic particles found in the nucleus?
protons and neutrons
The atomic number of an atom is always equal to the number of
protons in the nucleus
An atom of carbon-14 contains ____ protons, ____ neutrons, and ____ electrons
6, 8, 6
A neutral oxygen atom differs from an ion of oxygen (O2-) because the atom has
fewer electrons
Charged particle formed when an atom gains or loses electrons.
ion
Atom of an element that has the same number of protons as another atom of the same element, but a different number of neutrons.
isotope
Sum of the protons and neutrons in the nucleus of an atom.
mass number
The subatomic particles 14 6C and 14 7N are similar in that they both have the same
mass number
Experimental evidence indicates that the nucleus of an atom contains...
most of the mass of an atom
Subatomic particle with no electric charge
neutron
Which particle is electrically neutral?
neutron
The small, dense, positively charged center of an atom
nucleus
The total number of electrons in a neutral atom of every element is always equal to the atom's
number of protons
Two atoms will always have the same atomic number if they have the same
number of protons
The nucleus of an atom of 127I contains ____ protons and ____ neutrons
53, 74
The number of protons in an atom of hydrogen is
1
What are two discoveries from Rutherford's gold foil experiment
1. most of the alpha particles went through Au foil UNDEFLECTED, most of the atoms volume is simply a vacuum 2. the alpha particles that were deflected made a distinct and repetitive pattern, the nucleus is positive, dense center of an atom
What is the total number of neutrons in an atom of 19F?
10
What is the total number of electrons in a Mg atom?
12
The Al3+ ion has____ protons, ____ neutrons and ____ electrons
13, 14, 10
In which pair does each atom have the same number of neutrons?
15N and 16O
What is the total number of protons in an atom of 36Cl?
17
Which pair of atoms are isotopes of element x?
226 91X and 227 91X
How many electrons are in a neutral atom of 7 3Li?
3
What is the mass number of a 3 1H atom?
3
A sample of element X contains 90% of 35X atoms, 8% of 37X atoms, and 2% of 38X atoms. Calculate the average atomic mass.
35.22 amu
Draw an atomic model to represent Be2+
4 protons, 5 neutrons, 2 electrons
Draw an atomic model to represent 9Be
4 protons, 5 neutrons, 4 electrons
What is the mass number of an ion that consists of 20 protons, 20 neutrons, and 18 electrons?
40
Which pair of elements are isotopes?
40 19K and 42 19K
What is the symbol for an atom containing 20 protons and 22 neutrons?
Ca
If the nucleus of an atom is represented as 11X, the atom is
Na (sodium)
Compared to the charge and mass of a proton, an electron has
an opposite charge and a smaller mass
the smallest particle of an element that retains the properties of that element
atom
Weighted average of the masses of all the naturally occurring isotopes of an element.
atomic mass
All atoms of a given element must have the same
atomic number
Number of protons in the nucleus of an atom
atomic number
An isotope of which element has an atomic number of 6 and a mass number of 14?
carbon
The nucleus is the part of the atom that
contains most of the atom's total mass
Subatomic particle with negative charge
electron
Simplest type of a pure substance.
element
As a Na atom forms Na+ ion, the number of protons in its nucleus...
remains the same
How to tell is atoms are an isotope of an element
same number on bottom, different number on top