Atomic Structure

The nucleus of an atom is

• negatively charged and has a low density.

• negative charged and has a high density.

• positively charged and has a low density.

• positively charged and has a high density.

All atoms of the same element have the same

• number of protons.

• number of neutrons.

• mass number.

• mass.

This model was developed after J.J. Thompson discovered electrons, a particle smaller than an atom. Is shows electrons floating freely in a positive space.

• The "Plum Pudding Model" of the atom

• The "Rutherford Model" of the atom

• Democritus's model of the atom

• The "Quantum Mechanical Model" of the atom

Tags

NGSS.MS-PS1-1

Ernest Rutherford discovered that atoms were mostly _________________. 

• negatively charged

• positively charged

• electrons

• empty space. 

The atom is neutral because the number of protons is equal to the number of _____________.

Tags

NGSS.MS-PS1-1

Isotopes are atoms of the same element with different numbers of ____________ which results in different mass numbers.

Which of the following is NOT part of Dalton's atomic theory?

• All elements are composed of atoms.

• Atoms of the same element are alike.

• Atoms are always in motion.

• Atoms that combine do so in simple whole-number ratios.

Tags

NGSS.MS-PS1-5

The number of neutrons in the nucleus of an atoms can be calculated by

• adding together the numbers of electrons and protons.

• subtracting the number of protons from the number of electrons.

• subtracting the number of protons from the mass number.

• adding the mass number to the number of protons.

Which of these statements is FALSE?

• Electrons have a negative charge.

• Electrons have a mass of 1 amu.

• The nucleus of an atom is positively charged.

• The neutron is found in the nucleus of an atom.

The number 80 in the name bromine-80 represents

• the atomic number.

• the mass number.

• the sum of the protons and electrons.

• none of the above.