Simple Atomic Structure,home learning

Simple Atomic Structure,home learning

Simple atomic structure for home learning

Atomic number, mass number and electron arrangement. Check your learning with a 30 second 5 question quiz

Atomic Number and Mass Number.

  • The atomic number is the number of protons in the nucleus of an atom.
  • In a neutral atom the numbers of protons (+) and electrons (-) are the same.
  • The mass number is the total number of protons and neutrons in the nucleus of an atom.


But wot about the electrons?

    • Electrons are arranged in cloud like shells around the nucleus.
    • Shells closest to the nucleus fill up with electrons first.
    • The first shell is full with two electrons.The second and third shells are full with eight electrons.
    • For the first twenty elements remaining electrons go in the fourth shell.


The sodium atom



  • the atomic number is 11. There are 11 protons in the nucleus and eleven electrons in the shells around the nucleus.
  • Two electrons go in the first shell, eight in the second and the remaining electron goes in the third shell.
  • The electron configuration for sodium is Na(2,8,1). This is enough information to understand how the first 20 elements in the periodic table react with each other,
quick quiz

Lake Tikitapu

Lake Tikitapu

Lake Tikitapu

The blue lake

Picture Perfect with a violent past.

Twenty minutes out of Rotorua on the Tarawera road lies picturesque Tikitapu. An undulating track meanders around the lake and it takes 1.5 hours to complete if you stop to admire the stunning views. 

The scenery is 20, 000 years in the making and each hill and cliff face marks a significant volcanic event.

The hill that looks like a cuddly neck collar worn on long haul flights exploded into life 21000 years ago and is a rhyolite dome. Rhyollite is a thick viscous lava that melts at around 800 degrees celsius. It is simply referred to as North Dome.




Smooth and rounded or a bit crumpled.

Depends on which side of the lake you find yourself.

North Dome on the eastern shore has a beautifully rounded sculptured look. The lava flows appear this way because they have been liberally dusted with tephra (literally anything that falls from the sky) Dutch masters used the same technique, adding layers of paint till they got it right.

It is a slightly different story on the other side of the lake.  The lava front cooled and solidified forcing the rest to back up and crumple leaving a noticeable rib structure more typical of rhyolite flows. This happened about 18000 years ago.


Tikitapu lies on the fringe of the Okataina volcanic centre.

Not far away, Mount Tarawera was the scene of New Zealand’s most violent eruption in the last 500 years.

A rhyolitic dome split apart with very  little warning. Earthquake tremors were first felt in Rototrua  about 12.30am on 10 June 1886. Around 2am basalt lava rather than the usual rhyolite began erupting from the central dome of Mount Tarawera. 

Two hours later pyroclastic eruptions were occurring on Taraweras three main peaks. 





Better than a selfie

This work was painted by Charles Bloomfield who was renowned for his meticulous attention to detail. We can be reasonably certain this is an accurate representation of events

Towards the right of the painting Bloomfield has caught the moment basaltic lava at over 1000 degrees Celsius came in contact with the hydrothermal system underneath the old lake Rotomahana.

Like dropping water on a BBQ hotplate with gas turned up max the instantaneous production of colossal volumes of steam resulted in a phreatomagmatic explosion.

What goes up must come down. The column of scoria ash mud and steam reached a height of 10 kilometres .

The catastrophic collapse of this column would have projected hurricane speed surges of scalding hot debris outwards from the base destroying everything in its path

New Zealand Journal of Geology and Geophysics

I. A. Nairn (1979) Rotomahana—Waimangu eruption, 1886: base surge
and basalt magma, New Zealand Journal of Geology and Geophysics, 22:3, 363-378, DOI:
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