All elements have at least some radioactive isotopes.
For some elements no radioactive isotopes are known except those that are synthetic (see link to related question below).
For some other elements, there are both radioactive isotopes and stable isotopes in nature. (see link to related question below).
Some elements only have radioactive isotopes, and these are found in nature in at least trace quantities, they include (ordered by atomic number; those marked with * are normally only found in trace amounts in ore as radioactive decay products, and those with ** are distributed radioactive decay products found in trace amounts):
Period 5: technetium*
Period 6: promethium*, bismuth, polonium*, astatine*, radon**
Period 7: francium*, radium*, actinium*, thorium, protactinium*, uranium, neptunium*, plutonium**
The fact that all isotopes of bismuth are radioactive was only recently discovered.
Some elements are only know as a result of synthesis by human activity, and these are as follows:Period 7: americium, curium, berkelium, californium, einsteinium, fermium, mendelevium, nobelium, lawrencium, rutherfordium, dubnium, seaborgium, bohrium, hassium, meitnerium, darmstadtium, roentgenium, copernicium, and anything new that might come along.
bismuth
thorium
uranium
plutonium
curium
technetium
neptunium
protactinium
americium
radium
berkelium
californium
polonium
actinium
promethium
einsteinium
fermium
mendelevium
radon
dubnium
rutherfordium
lawrencium
astatine
bohrium
seaborgium
hassium
nobelium
francium
ununtrium
roentgenium
meitnerium
ununbium
darmstadtium
ununquadium
ununhexium
ununoctium
Not all elements are radioactive. Only elements having atomic number more than 83 are considered having radioactive nature (radio-isotopes). The elements with atomic number less than 83 are considered stable.
OLDER ANSWER:Theoretically they all are, it is just a matter of decay-speed(radioactivity).
In general, the elements with higher numbers (more protons and neutrons) are more unstable, and thus decay faster.
26 Iron is considered stable, but higher then 84 Polonium is considered active.
There is two companies that are known for selling contemporary items. The most well known being Ikea, the second most important being Walmart.
Some examples of radioactive elements on the periodic table include uranium, thorium, radium, and plutonium. These elements have unstable atomic nuclei that decay over time, emitting radiation in the process.
The period on the periodic table of elements that contains radioactive elements is the 7th period. These elements are called actinides and include elements such as uranium and plutonium.
The group that contains only radioactive elements is the actinide series, which includes elements 89 to 103 on the periodic table. These elements are all radioactive due to their unstable atomic nuclei.
In the Periodic Table of Elements there are: 118 Observed Elements 114 Officially Discovered Elements 112 Officially named Elements 92 Naturally Occuring Elements 83 Non-radioactive elements
Radioactive elements do not have a specific chemical formula, as they can be any element on the periodic table with unstable nuclei that emit radiation. Some examples of radioactive elements include uranium, radium, and thorium.
Group 3 of the periodic table contains many of the radioactive elements.
Radioactive elements exist in all groups of the periodic table.
Some examples of radioactive elements on the periodic table include uranium, thorium, radium, and plutonium. These elements have unstable atomic nuclei that decay over time, emitting radiation in the process.
Radioactive elements exist in all groups of the periodic table.
The period on the periodic table of elements that contains radioactive elements is the 7th period. These elements are called actinides and include elements such as uranium and plutonium.
all elements after uranium (atomic number 92) are radioactive.
Radioactive atoms can be found throughout the periodic table. They can be naturally occurring elements like uranium and thorium, or they can be created synthetically in laboratories by bombarding stable atoms with particles.
Some radioactive elements in the periodic table are radium, uranium, plutonium, thorium, polonium, radon, francium, astatine, radium, and curium.
Lanthanides and Actinides probably
All elements comprising the period 7 in the periodic table are radioactive. In total this period has 32 elements.
This is hard to answer.All elements have radioactive isotopes.Some elements have no known stable isotopes.It might be more instructive to put the periodic table aside and look at a table of nuclides instead. There's a link to one in the Related Links section.
You think probable to isotopes; but the most important isotope of artificial radioactive elements is included in the periodic table.