For each electron, the Paint event handler uses the Graphics object's RotateTransform and TranslateTransform methods to prepare to draw rotated and translated objects. It then draws an ellipse centered at the origin. The rotation and scaling position it appropriately for the atom.

Then code then uses trigonometry to figure out where the electron should be on its orbit and draws a circle there.

The angle m_Alpha determines the electrons' positions. Note that the code multiplies m_Alpha by different values for the different electrons so they move at different speeds.

Private m_Alpha As Single = 0
Private Const DALPHA As Single = PI / 10

' Draw the atom.
Private Sub Form1_Paint(ByVal sender As Object, ByVal e As _
    System.Windows.Forms.PaintEventArgs) Handles _
    MyBase.Paint
    Const DTHETA As Double = Math.PI / 5
    Static theta As Double = 0

    e.Graphics.Clear(Me.BackColor)
    e.Graphics.SmoothingMode = _
        Drawing2D.SmoothingMode.AntiAlias
    theta += DTHETA

    Const E_RADIUS As Integer = 3
    Dim cx As Integer = 50
    Dim cy As Integer = 50
    Dim rx As Integer = CInt(45)
    Dim ry As Integer = CInt(15)
    Dim rect As New Rectangle(-rx, -ry, 2 * rx, 2 * ry)
    Dim x, y As Double
    e.Graphics.RotateTransform(60, _
        Drawing2D.MatrixOrder.Append)
    e.Graphics.TranslateTransform(cx, cy, _
        Drawing2D.MatrixOrder.Append)
    e.Graphics.DrawEllipse(Pens.Red, rect)
    x = rx * Cos(theta)
    y = ry * Sin(theta)
    e.Graphics.FillEllipse(Brushes.Red, _
        CInt(x - E_RADIUS), CInt(y - E_RADIUS), _
        2 * E_RADIUS, 2 * E_RADIUS)

    e.Graphics.ResetTransform()
    e.Graphics.RotateTransform(-60, _
        Drawing2D.MatrixOrder.Append)
    e.Graphics.TranslateTransform(cx, cy, _
        Drawing2D.MatrixOrder.Append)
    e.Graphics.DrawEllipse(Pens.Red, rect)
    x = rx * Cos(-theta * 0.9)
    y = ry * Sin(-theta * 0.9)
    e.Graphics.FillEllipse(Brushes.Green, _
        CInt(x - E_RADIUS), CInt(y - E_RADIUS), _
        2 * E_RADIUS, 2 * E_RADIUS)

    e.Graphics.ResetTransform()
    e.Graphics.TranslateTransform(cx, cy, _
        Drawing2D.MatrixOrder.Append)
    e.Graphics.DrawEllipse(Pens.Red, rect)
    x = rx * Cos(theta * 0.8)
    y = ry * Sin(theta * 0.8)
    e.Graphics.FillEllipse(Brushes.Blue, _
        CInt(x - E_RADIUS), CInt(y - E_RADIUS), _
        2 * E_RADIUS, 2 * E_RADIUS)

    e.Graphics.ResetTransform()
    Const N_RADIUS As Integer = 4
    e.Graphics.FillEllipse(Brushes.Black, _
        cx - N_RADIUS, cy - N_RADIUS, _
        2 * N_RADIUS, 2 * N_RADIUS)
End Sub