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MOVE

Function

MOVE is one of the two program modes in the BUILD menu - the other is DRAW.

It is convenient to discuss them together.

Remarks

In DRAW mode there is always an "active" atom, indicated by a red cross.

In DRAW mode when you select an atom other than the active atom a bond is added and the new atom becomes the active atom for the next operation.

The new atom will be assigned the Current Element type and the new bond will be assigned the Current Bond Type.

In MOVE mode there is no "active" atom.

Selecting either a new or existing atom moves the program to DRAW mode.

From DRAW mode, either select the active atom or select the MOVE command on the menu.

In MOVE mode, if the element symbol of a selected atom is different from the Current Element then the atom will be assigned the Current Element symbol.

In MOVE mode, if you select a bond whose type is different from the Current Bond Type then the bond is assigned the Current Bond Type.

Repeatedly selecting an atom switches (toggles) the program between MOVE and DRAW modes.

On entering the BUILD menu the current settings are C, SING, MOVE.

Suppose we wish to construct the skeleton fragment (i) - see below.

A possible sequence of actions is tabulated in (ii).

You are recommended to carry out this exercise in the same order of steps and check the results of each action against this table.

Step 1 indicates that when a new atom is created it becomes the active atom.

An active atom is indicated by a red + beside the atom.

The program state switches to DRAW.

When the program state is DRAW then successive selection of new positions creates bonds from old atom to new atom, with new atom becoming the active atom.

This is illustrated by steps 2 - 6.

In step 7 we return to an existing atom (atom 1).

The program state switches from DRAW to MOVE and now no atom is active.

This allows us to branch to a different part of the diagram, as we do in step 8.

It is evident from the tabulation that:

when an atom is active the program state is DRAW

when no atom is active the program state is MOVE.

When an atom is active we can switch from DRAW to MOVE

either by selecting the menu option MOVE

or by re-selecting the active atom (see steps 11 and 16).

Steps 14 - 16 and 17 - 18 illustrate that we can use the BUILD menu to edit element types and bond types - there is no need to select the EDIT menu for such simple editing.

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