Elements and the periodic table

Oxygen has how many electrons?

Who discovered the proton?

Who used the plum pudding model to describe the atom?

Which model stated that electrons are in energy levels and electron clouds?

Who discovered the neutron?

The nucleus includes

True or false: The Greek model stated that the four elements were earth, wind, water, and fire

True or false: alkaline earth metals are more reactive than alkali metals

which class of elements is the largest?

Who discovered that electrons moved around the nucleus in orbitals?

How many protons does Br^- have?

True or false: a cation is an element that loses electrons

True or false: the electron is bigger in mass than the proton

Which group of elements is nonreactive?

which has a larger atomic radius: Na or K?

Mendeleev organized his periodic table by

How many neutrons does Cr-53 have?

What is atomic number?

Which has a larger ionization energy: C or N?

When an element becomes an isotope it...