He postulated the Nuclear Model of an Atom

• Ernest Rutherford

• Neils Bohr

• J.J. Thomson

• Henry Moseley

This subatomic particle has a mass almost equal to the mass of the proton.

• Electron

• Proton

• Neutron

• Nucleus

Why is the r-process rapid?

• because proton capture is fast that an unstable nucleus may combine with another proton before undergoing decay

• because neutron capture is fast that an unstable nucleus may combine with another neutron before undergoing decay

• because proton capture is slow that an unstable nucleus may combine with a neutron before undergoing decay

• because neutron capture is slow that an unstable nucleus may combine with a proton before undergoing decay

What does “s” in s-process means?

• supernova

• synthesis

• speed

• slow

Which of the following has zero mass and negative charge?

• alpha particle

• beta particle

• x-ray

• gamma ray

Which of the following elements has one proton and two neutrons?

• Tritium

• Deuterium

• Helium-3

• Helium-4

Which of the following is true when the temperature of the universe was 3 × 10¹⁰ K?

• There were more protons than neutrons in the universe.

• The nuclei combined with electrons to produce neutral atoms.

• Helium nuclei outnumbered hydrogen nuclei in the universe.

• The universe was filled with combined protons and electrons, with neutrons roaming freely in space.

Which of the following refers to the explosion of a star?

• 
• 
• 
• 

Which of the following elements comprise the core of a white dwarf?

• Hydrogen

• Nitrogen

• Carbon

• Helium